Earth

According to the World Health Organization, cardiovascular (CV) disease has become the leading cause of death worldwide. However, vascular regeneration is a promising treatment for cardiovascular disease. Remodeling the endothelium - i.e., forming a confluent vascular endothelial cell monolayer on the lumen - plays a vital role in this process.

Rapid endothelialization poses challenges, however, when using existing synthetic biomaterials, due to their static properties. Such materials cannot offer dynamic, on-demand means for manipulating specific vascular endothelial cell functions at different stages of endothelium remodeling.

A joint research group led by Dr. DU Xuemin at the Shenzhen Institutes of Advanced Technology (SIAT) of the Chinese Academy of Sciences recently demonstrated a remote-controlled "smart" platform that effectively directs programmed vascular endothelium remodeling in a temporally controllable manner. The study was published in National Science Review [2019].

The researchers first prepared a bilayer platform with programmable surface topographies using a shape-memory polymer and gold nanorods acting as a photothermal agent. The bilayer platform allowed on-demand manipulation of vascular endothelial cell functions, thus meeting the requirements of endothelium remodeling.

During the endothelialization process of native blood vessels, vascular endothelial cells and progenitor cells are first recruited to regeneration sites. This is followed by the adhesion and spreading of the vascular endothelial cells to form a confluent vascular endothelial cell monolayer. In the human body, such a process is implemented through extracellular matrix (ECM)-mediated stepwise modulation of vascular endothelial cell functions at different stages.

"The new platform possesses originally stable anisotropic microgroove array topography. This topography can significantly direct cell polarization and thereby enhance the collective migration of vascular endothelial cells," said ZHAO Qilong, first author of the study.

Upon 10 s of near-infrared (NIR) irradiation, the heat generated on the bottom layer induced the surface topographies of the platform to change from their original anisotropic microgroove array to a permanent isotropic micropillar array.

The focal adhesion and spreading of vascular endothelial cells were subsequently promoted at the later stage of endothelialization by the platform after the topographies were changed. The remote-controlled "smart" platform promoted different functions of vascular endothelial cells in turn, thus mimicking dynamic ECM-mediated effects throughout the endothelialization process for the first time using synthetic biomaterials.

"Traditionally, biomaterials and tissue engineering scaffolds offer suitable platforms to support cell attachment and ingrowth. We aim to develop biomaterials with dynamic properties to actively modulate different cell functions in specific spatiotemporal manners, just like the native ECM in our bodies. We believe biomaterials with dynamic properties will contribute to the progress of wound healing and complex tissue/organ regeneration," said Dr. DU Xuemin from SIAT.

People who repeatedly encounter a fake news item may feel less and less unethical about sharing it on social media, even when they don't believe the information, research indicates.

In a series of experiments involving more than 2,500 people, Daniel A. Effron, a London Business School associate professor of organizational behavior, and Medha Raj, a PhD student at the University of Southern California, found that seeing a fake headline just once leads individuals to temper their disapproval of the misinformation when they see it a second, third, or fourth time.

The findings, published in Psychological Science, have important implications for policymakers and social media companies trying to curb the spread of misinformation online, Effron says.

"We suggest that efforts to fight misinformation should consider how people judge the morality of spreading it, not just whether they believe it," he says.

Across five experiments, Effron and Raj asked online survey participants to rate how unethical or acceptable they thought it would be to publish a fake headline, and how likely they would be to "like", share, and block or unfollow the person who posted it.

As they expected, the researchers found that participants rated headlines they had seen more than once as less unethical to publish than headlines they were shown for the first time. Participants also said they were more likely to "like" and share a previously seen headline and less likely to block or unfollow the person who posted it. What's more, they did not rate previously seen headline as significantly more accurate than new ones.

"Thus, our main results cannot be explained by a tendency to misremember false headlines as true," the researchers write.

Effron and Raj note that efforts to curtail misinformation typically focus on helping people distinguish fact from fiction. Facebook, for example, has tried informing users when they try to share news that fact-checkers have flagged as false. But such strategies may fail if users feel more comfortable sharing misinformation they know is fake when they have seen it before.

The researchers theorize that repeating misinformation lends it a "ring of truthfulness" that can increase people's tendency to give it a moral pass, regardless of whether they believe it. Merely imagining misinformation as if it were true can have a similar effect. Effron's earlier research shows that people are more likely to excuse a blatant falsehood after imagining how it could have been true if the past had been different.

"The results should be of interest to citizens of contemporary democracies," Effron adds. "Misinformation can stoke political polarization and undermine democracy, so it is important for people to understand when and why it spreads."

As awareness increases about the health danger of radon gas, more people are making the decision to test their homes for the deadly gas. A University of Calgary led study finds the only reliable way to measure exposure to radon gas is with a long-term testing kit, which takes readings within the home for 90 or more days.

"Radon gas levels can fluctuate wildly day to day," says Dr. Aaron Goodarzi, PhD, assistant professor in the departments of Biochemistry & Molecular Biology and Oncology and member of the Arnie Charbonneau Cancer Institute at the Cumming School of Medicine (CSM). "Short term tests can give a false sense of alarm, or worse, a false sense of security as they cannot precisely predict long term exposure."

Researchers placed two test kits, a short term (five-day) and long term (90-day) in the same homes. Tests were conducted during summer and winter months. Findings showed the short-term kits were imprecise up to 99 percent of the time when compared to a long term test.

Radon is a known carcinogen. Health Canada lists radon as the number one cause of lung cancer in non-smokers. The gas is naturally occurring, colourless, and odorless. It can accumulate to unnaturally high and dangerous levels in homes. Health Canada has promoted the use of long-term testing kits for some time.

"Our recommendation was based on research from international authorities including the US and Europe," says Kelley Bush, manager, radon education and awareness Health Canada. "This research is critical because it provides Canadian data that confirms the value of long term testing."

Goodarzi has also been working with the Real Estate Council of Alberta (RECA) to educate realtors against using short term radon kits for real estate transactions.

"RECA is appreciative of the assistance provided by Dr. Goodarzi in the development of education enabling real estate professionals to advise buyers and sellers to take radon into consideration during the purchase and sale of a home, in the absence of reliable short-term testing," says Joseph Fernandez, director of education programs at RECA. "All real estate professionals have completed radon related education and new professionals will be required to complete it before entering the real estate profession."

The findings also show the Prairies are home to the second highest radon exposed population on Earth. The pan-Canadian scientist and physician led Evict Radon research initiative is now recruiting participation from all Canadians.

The research is aimed at gathering as much data as possible to understand and ultimately defeat Canadian's exposure to radon problem.

"We need to know exactly what factors influence high and low radon in Canadian homes. It's not just in the Prairies, we know of high concentrations in areas throughout the country," says Goodarzi. "This is easily one of the most preventable forms of environmentally-caused cancer. We have already learned so much from the work we've done in Alberta and Saskatchewan to test for and mitigate radon. We plan to build on that."

In addition to the data gathered on short-term testing kits, Goodarzi's team was also able to get a better understanding of how the size, design and age of home are related to radon gas exposure.

Star-quakes recorded by NASA's Kepler space telescope have helped answer a long-standing question about the age of the "thick disc" of the Milky Way.

In a paper published in the journal Monthly Notices of the Royal Astronomical Society, a team of 38 scientists led by researchers from Australia's ARC Centre of Excellence for All Sky Astrophysics in Three Dimensions (ASTRO-3D) use data from the now-defunct probe to calculate that the disc is about 10 billion years old.

"This finding clears up a mystery," says lead author Dr Sanjib Sharma from ASTRO-3D and Australia's University of Sydney.

"Earlier data about the age distribution of stars in the disc didn't agree with the models constructed to describe it, but no one knew where the error lay - in the data or the models. Now we're pretty sure we've found it."

The Milky Way - like many other spiral galaxies - consists of two disc-like structures, known as thick and thin. The thick disc contains only about 20 per cent of the Galaxy's total stars, and, based on its vertical puffiness and composition, is thought to be the older of the pair.

To find out just how much older, Dr Sharma and colleagues used a method known as asteroseismology - a way of identifying the internal structures of stars by measuring their oscillations from star quakes.

"The quakes generate soundwaves inside the stars that make them ring, or vibrate," explains co-author Associate Professor Dennis Stello from ASTRO-3D and the University of New South Wales.

"The frequencies produced tell us things about the stars' internal properties, including their age. It's a bit like identifying a violin as a Stradivarius by listening to the sound it makes."

This age-dating allows researchers to essentially look back in time and discern the period in the Universe's history when the Milky Way formed; a practice known as Galactic-archaeology.

Not that the researchers actually hear the sound generated by star-quakes. Instead, they look for how the internal movement is reflected in changes to brightness.

"Stars are just spherical instruments full of gas," says Sharma, "but their vibrations are tiny, so we have to look very carefully.

"The exquisite brightness measurements made by Kepler were ideal for that. The telescope was so sensitive it would have been able to detect the dimming of a car headlight as a flea walked across it."

The data delivered by the telescope during the four years after it was launched in 2009 presented a problem for astronomers. The information suggested there were more younger stars in the thick disc than models predicted.

The question confronting scientists was stark: were the models wrong, or was the data incomplete?

In 2013, however, Kepler broke down, and NASA reprogrammed it to continue working on a reduced capacity - a period that became known as the K2 mission. The project involved observing many different parts of the sky for 80 days at a time.

The first tranche of this data represented a rich new source for Dr Sharma and colleagues from Macquarie University, Australian National University, University of New South Wales and the University of Western Australia. They were joined in their analysis by others from institutions in the US, Germany, Austria, Italy, Denmark, Slovenia and Sweden.

A fresh spectroscopic analysis revealed that the chemical composition incorporated in the existing models for stars in the thick disc was wrong, which affected the prediction of their ages. Taking this into account, the researchers found that the observed asteroseismic data now fell into "excellent agreement" with model predictions.

The results provide a strong indirect verification of the analytical power of asteroseismology to estimate ages, says Professor Stello.

He added that additional data still to be analysed from K2, combined with new information gathered by NASA's Transiting Exoplanet Survey Satellite (TESS), will result in accurate estimates for the ages of even more stars within the disc and this will help us to unravel the formation history of the Milky Way.

OAK BROOK, Ill. - A sophisticated type of artificial intelligence (AI) can detect clinically meaningful chest X-ray findings as effectively as experienced radiologists, according to a study published in the journal Radiology. Researchers said their findings, based on a type of AI called deep learning, could provide a valuable resource for the future development of AI chest radiography models.

Chest radiography, or X-ray, one of the most common imaging exams worldwide, is performed to help diagnose the source of symptoms like cough, fever and pain. Despite its popularity, the exam has limitations.

"We've found that there is a lot of subjectivity in chest X-ray interpretation," said study co-author Shravya Shetty, an engineering lead at Google Health in Palo Alto, California. "Significant inter-reader variability and suboptimal sensitivity for the detection of important clinical findings can limit its effectiveness."

Deep learning, a sophisticated type of AI in which the computer can be trained to recognize subtle patterns, has the potential to improve chest X-ray interpretation, but it too has limitations. For instance, results derived from one group of patients cannot always be generalized to the population at large.

Researchers at Google Health developed deep learning models for chest X-ray interpretation that overcome some of these limitations. They used two large datasets to develop, train and test the models. The first dataset consisted of more than 750,000 images from five hospitals in India, while the second set included 112,120 images made publicly available by the National Institutes of Health (NIH).

A panel of radiologists convened to create the reference standards for certain abnormalities visible on chest X-rays used to train the models.

"Chest X-ray interpretation is often a qualitative assessment, which is problematic from deep learning standpoint," said Daniel Tse, M.D., product manager at Google Health. "By using a large, diverse set of chest X-ray data and panel-based adjudication, we were able to produce more reliable evaluation for the models."

Tests of the deep learning models showed that they performed on par with radiologists in detecting four findings on frontal chest X-rays, including fractures, nodules or masses, opacity (an abnormal appearance on X-rays often indicative of disease) and pneumothorax (the presence of air or gas in the cavity between the lungs and the chest wall).

Radiologist adjudication led to increased expert consensus of the labels used for model tuning and performance evaluation. The overall consensus increased from just over 41 percent after the initial read to more than almost 97 percent after adjudication.

The rigorous model evaluation techniques have advantages over existing methods, researchers said. By beginning with a broad, hospital-based clinical image set, and then sampling a diverse set of cases and reporting population adjusted metrics, the results are more representative and comparable. Additionally, radiologist adjudication provides a reference standard that can be both more sensitive and more consistent than other methods.

"We believe the data sampling used in this work helps to more accurately represent the incidence for these conditions," Dr. Tse said. "Moving forward, deep learning can provide a useful resource to facilitate the continued development of clinically useful AI models for chest radiography."

The research team has made the expert-adjudicated labels for thousands of NIH images available for use by other researchers at the following link: https://cloud.google.com/healthcare/docs/resources/public-datasets/nih-chest#additional_labels.

"The NIH database is a very important resource, but the current labels are noisy, and this makes it hard to interpret the results published on this data," Shetty said. "We hope that the release of our labels will help further research in this field."

A specialised system of ducts transports bile and enzymes from the liver and pancreas to the intestine. In a new study, researchers from the University of Copenhagen have shown how this ductal system is formed. The new knowledge can help understanding how congenital diseases in that part of the body arise.

The body's liver, gallbladder and pancreas are connected by a specialised system of ducts, the so-called hepatopancreatic ductal system, that are leading to the intestine. Bile, digestive enzymes and other secretions flow through the ducts, which are therefore essential for enabling the digestion of food and the absorption of nutrients.

Now, researchers from the University of Copenhagen have investigated how this ductal system forms. The results have been published in the scientific journal Nature Communications.

The new findings may help to better understand rare diseases in the ductal system, such as biliary atresia. This is a disease in children where the ductal network is not properly developed, which can in some cases lead to severe liver damage.

'We know very little about diseases such as biliary atresia, where the ducts are blocked or completely absent. In order to understand how and why these diseases occur, it is important to find out how the entire ductal system forms during development,' says Associate Professor and co-author of the study Elke Ober, Novo Nordisk Foundation Center for Stem Cell Biology (DanStem).

'In the study, we show that the ductal system is formed in a multi-step process, with different cell rearrangement and remodelling phases taking place until the ducts are open and fully developed. We have also found an important group of genes that control part of this process,' says co-author and postdoc Ilcim Thestrup, who performed her PhD thesis at DanStem.

The researchers have characterised the formation of the ductal system in zebrafish. The system is formed during embryonic stages. In humans, this takes several weeks, while in zebrafish the ductal system develops in about 48 hours.

Zebrafish resemble humans in many ways: Organ systems, functional cell types and signals controlling developmental processes are highly similar. This together with the fast embryonic development, are the reason why Elke Ober's research group chose to use zebrafish for this study.

In addition to experiments with zebrafish, the researchers examined human tissue samples to investigate if the group of genes, which they found in zebrafish, is also expressed in humans.

'We found a group of genes called EphB and EphrinB in the zebrafish, which instruct part of the development of the ductal system. We have shown that this group is also expressed in humans. This indicates that these genes may play the same or a similar role in the formation of these ducts in humans and if misregulated, they may potentially cause ductal diseases,' says Elke Ober.

Graphene Flagship partners the University of Bologna, Politecnico di Milano, CNR, NEST, Italcementi HeidelbergCement Group, the Israel Institute of Technology, Eindhoven University of Technology, and the University of Cambridge have developed a graphene-titania photocatalyst that degrades up to 70% more atmospheric nitrogen oxides (NOx) than standard titania nanoparticles in tests on real pollutants.

Atmospheric pollution is a growing problem, particularly in urban areas and in less developed countries. According to the World Health Organization, one out of every nine deaths can be attributed to diseases caused by air pollution. Organic pollutants, such as nitrogen oxides and volatile compounds, are the main cause of this, and they are mostly emitted by vehicle exhausts and industry.

To address the problem, researchers are continually on the hunt for new ways to remove more pollutants from the atmosphere, and photocatalysts such as titania are a great way to do this. When titania is exposed to sunlight, it degrades nitrogen oxides - which are very harmful to human health - and volatile organic compounds present at the surface, oxidising them into inert or harmless products.

Now, the Graphene Flagship team working on photocatalytic coatings, coordinated by Italcementi, HeidelbergCement Group, Italy, developed a new graphene-titania composite with significantly more powerful photodegradation properties than bare titania. "We answered the Flagship's call and decided to couple graphene to the most-used photocatalyst, titania, to boost the photocatalytic action," comments Marco Goisis, the research coordinator at Italcementi. "Photocatalysis is one of the most powerful ways we have to depollute the environment, because the process does not consume the photocatalysts. It is a reaction activated by solar light," he continues.

By performing liquid-phase exfoliation of graphite - a process that creates graphene - in the presence of titania nanoparticles, using only water and atmospheric pressure, they created a new graphene-titania nanocomposite that can be coated on the surface of materials to passively remove pollutants from the air. If the coating is applied to concrete on the street or on the walls of buildings, the harmless photodegradation products could be washed away by rain or wind, or manually cleaned off.

To measure the photodegradation effects, the team tested the new photocatalyst against NOx and recorded a sound improvement in photocatalytic degradation of nitrogen oxides compared to standard titania. They also used rhodamine B as a model for volatile organic pollutants, as its molecular structure closely resembles those of pollutants emitted by vehicles, industry and agriculture. They found that 40% more rhodamine B was degraded by the graphene-titania composite than by titania alone, in water under UV irradiation. "Coupling graphene to titania gave us excellent results in powder form - and it could be applied to different materials, of which concrete is a good example for the widespread use, helping us to achieve a healthier environment. It is low-maintenance and environmentally friendly, as it just requires the sun's energy and no other input," Goisis says. But there are challenges to be addressed before this can be used on a commercial scale. Cheaper methods to mass-produce graphene are needed. Interactions between the catalyst and the host material need to be deepened as well as studies into the long-term stability of the photocatalyst in the outdoor environment.

Ultrafast transient absorption spectroscopy measurements revealed an electron transfer process from titania to the graphene flakes, decreasing the charge recombination rate and increasing the efficiency of reactive species photoproduction - meaning more pollutant molecules could be degraded.

Xinliang Feng, Graphene Flagship Work Package Leader for Functional Foams and Coatings, explains: "Photocatalysis in a cementitious matrix, applied to buildings, could have a large effect to decrease air pollution by reducing NOx and enabling self-cleaning of the surfaces - the so-called "smog-eating" effect. Graphene could help to improve the photocatalytic behaviour of catalysts like titania and enhance the mechanical properties of cement. In this publication, Graphene Flagship partners have prepared a graphene-titania composite via a one-step procedure to widen and improve the ground-breaking invention of "smog-eating" cement. The prepared composite showed enhanced photocatalytic activity, degrading up to 40% more pollutants than pristine titania in the model study, and up to 70% more NOx with a similar procedure. Moreover, the mechanism underlying this improvement was briefly studied using ultrafast transient absorption spectroscopy."

Enrico Borgarello, Global Product Innovation Director at Italcementi, part of the HeidelbergCement Group, one of the world's largest producers of cement, comments: "Integrating graphene into titania to create a new nanocomposite was a success. The nanocomposite showed a strong improvement in the photocatalytic degradation of atmospheric NOx boosting the action of titania. This is a very significant result, and we look forward to the implementation of the photocatalytic nanocomposite for a better quality of air in the near future."

The reasons to incorporate graphene into concrete do not stop here. Italcementi is also working on another product - an electrically conductive graphene concrete composite, which was showcased at Mobile World Congress in February this year. When included as a layer in flooring, it could release heat when an electrical current is passed through it. Goisis comments: "You could heat your room, or the pavement, without using water from a tank or boiler. This opens the door to innovation for the smart cities of the future - particularly to self-sensing concrete," which could detect stress or strain in concrete structures and monitor for structural defects, providing warning signals if the structural integrity is close to failure.

Andrea C. Ferrari, Science and Technology Officer of the Graphene Flagship and Chair of its Management Panel, adds: "An ever-increasing number of companies are now partners, or associate members of the Graphene Flagship, since they recognize the potential for new and improved technologies. In this work, Italcementi, leader in Italy in the field of building materials, demonstrated a clear application of graphene for the degradation of environment pollutants. This can not only have commercial benefits, but, most importantly, benefit of society by resulting in a cleaner and healthier environment."

Chemolithotrophic microorganisms derive their energy from inorganic sources. Research into the physiological processes of these organisms - which are grown on meteorite - provides new insights into the potential of extraterrestrial materials as a source of accessible nutrients and energy for microorganisms of the early Earth. Meteorites may have delivered a variety of essential compounds facilitating the evolution of life, as we know it on Earth.

An international team around astrobiologist Tetyana Milojevic from the University of Vienna explored the physiology and metal-microbial interface of the extreme metallophilic archaeon Metallosphaera sedula, living on and interacting with extraterrestrial material, meteorite Northwest Africa 1172 (NWA 1172). Assessing the biogenicity based on extraterrestrial materials provides a valuable source of information for exploring the putative extraterrestrial bioinorganic chemistry that might have occurred in the Solar System.

Archaeon prefers meteorites

Cells of M. sedula rapidly colonize the meteoritic material, much faster than the minerals of terrestrial origin. "Meteorite-fitness seems to be more beneficial for this ancient microorganism than a diet on terrestrial mineral sources. NWA 1172 is a multimetallic material, which may provide much more trace metals to facilitate metabolic activity and microbial growth. Moreover, the porosity of NWA 1172 might also reflect the superior growth rate of M. sedula", says Tetyana Milojevic.

Investigations on nanometer scale

The scientists traced the trafficking of meteorite inorganic constituents into a microbial cell and investigated iron redox behavior. They analyzed the meteorite-microbial interface at nanometer scale spatial resolution. Combining several analytical spectroscopy techniques with transmission electron microscopy, the researchers revealed a set of biogeochemical fingerprints left upon M. sedula growth on the NWA 1172 meteorite. "Our investigations validate the ability of M. sedula to perform the biotransformation of meteorite minerals, unravel microbial fingerprints left on meteorite material, and provide the next step towards an understanding of meteorite biogeochemistry", concludes Milojevic.

VTT researchers were able to transmit light in wood-based fibre. Optical fibre made of cellulose is best suited for sensors that benefit from the biodegradability of the material. In the future, optical cellulose fibre may allow detecting changes in the moisture level of buildings.

- The core of the new optical fibre is made of cellulose, modified for the purpose using ionic solvents developed by VTT. Around the core, we made a cladding out of cellulose acetate. The R&D is still in its initial phases, so we do not yet know all the applications the new optical fibre could lend itself to, says Senior Scientist Hannes Orelma from VTT.

Light travels in the fibre, because the core is surrounded by cladding material with a lower index of refraction. Light is kept in the core since it is reflected back into the core from the interface of the core and the cladding.

- We have tested the suitability of the fibre for measuring moisture levels. Using a length of fibre of a few centimetres, we have already succeeded to increase the attenuation of light transmitted in the fibre many orders of magnitudes, says Research Scientist Ari Hokkanen from VTT.

Cellulose has properties making it suited for use in optical fibre sensors: The material used in cellulose fibres can in itself react with the substances being measured and absorb them, which is difficult for glass or plastic fibres. Cellulose is also easy to modify as regards, for instance, the index of refraction. Cellulose effectively absorbs and releases water, which can be measured by the change in the attenuation of light transmitted in the fibre. In addition, cellulose is biodegradable, and the fibre used for the sensor can be disposed of with biowaste.

Cellulose-based fibre opens up new opportunities for sensor applications, but it will not compete with glass-based optical fibres in telecommunications applications.

The development of the optical fibre began in VTT's iBex programme, which allows the researchers involved to implement fascinating solutions to global challenges. Currently, the R&D continues in the FinnCERES flagship programme in collaboration with VTT and Aalto University.

Researchers find new way to convert carbon dioxide into a usable fuel source.

The concentration of carbon dioxide in our atmosphere is steadily increasing, and many scientists believe that it is causing impacts in our environment. Recently, scientists have sought ways to recapture some of the carbon in the atmosphere and potentially turn it into usable fuel — which would be a holy grail for sustainable energy production.

In a recent study from the U.S. Department of Energy’s (DOE) Argonne National Laboratory, scientists have used sunlight and a catalyst largely made of copper to transform carbon dioxide to methanol. A liquid fuel, methanol offers the potential for industry to find an additional source to meet America’s energy needs.

“Carbon dioxide is such a stable molecule and it results from the burning of basically everything, so the question is how do we fight nature and go from a really stable end product to something useful and energy rich.” — Argonne Distinguished Fellow Tijana Rajh

The study describes a photocatalyst made of cuprous oxide (Cu­2O), a semiconductor that when exposed to light can produce electrons that become available to react with, or reduce, many compounds. After being excited, electrons leave a positive hole in the catalyst’s lower-energy valence band that, in turn, can oxidize water.

“This photocatalyst is particularly exciting because it has one of the most negative conduction bands that we’ve used, which means that the electrons have more potential energy available to do reactions,” said Argonne distinguished fellow Tijana Rajh, an author of the study.

Previous attempts to use photocatalysts, such as titanium dioxide, to reduce carbon dioxide tended to produce a whole mish-mash of various products, ranging from aldehydes to methane. The lack of selectivity of these reactions made it difficult to segregate a usable fuel stream, Rajh explained.

“Carbon dioxide is such a stable molecule and it results from the burning of basically everything, so the question is how do we fight nature and go from a really stable end product to something useful and energy rich,” Rajh said.

The idea for transforming carbon dioxide into useful energy comes from the one place in nature where this happens regularly. “We had this idea of copying photosynthesis, which uses carbon dioxide to make food, so why couldn’t we use it to make fuel” Rajh said. “It turns out to be a complex problem, because to make methanol, you need not just one electron but six.”

By switching from titanium dioxide to cuprous oxide, scientists developed a catalyst that not only had a more negative conduction band but that would also be dramatically more selective in terms of its products. This selectivity results not only from the chemistry of cuprous oxide but from the geometry of the catalyst itself.

“With nanoscience, we start having the ability to meddle with the surfaces to induce certain hotspots or change the surface structure, cause strain or certain surface sites to expose differently than they are in the bulk,” Rajh said.

Because of this “meddling,” Rajh and Argonne postdoctoral researcher Yimin Wu, now an assistant professor at the University of Waterloo, managed to create a catalyst with a bit of a split personality. The cuprous oxide microparticles they developed have different facets, much like a diamond has different facets. Many of the facets of the microparticle are inert, but one is very active in driving the reduction of carbon dioxide to methanol.

According to Rajh, the reason that this facet is so active lies in two unique aspects.  First, the carbon dioxide molecule bonds to it in such a way that the structure of the molecule actually bends slightly, diminishing the amount of energy it takes to reduce. Second, water molecules are also absorbed very near to where the carbon dioxide molecules are absorbed.

“In order to make fuel, you not only need to have carbon dioxide to be reduced, you need to have water to be oxidized,” Rajh said. “Also, adsorption conformation in photocatalysis is extremely important — if you have one molecule of carbon dioxide absorbed in one way, it might be completely useless. But if it is in a bent structure, it lowers the energy to be reduced.”

Argonne scientists also used scanning fluorescence X-ray microscopy at Argonne’s Advanced Photon Source (APS) and transmission electron microscopy at the Center for Nanoscale Materials (CNM) to reveal the nature of the faceted cuprous oxide microparticles. The APS and CNM are both DOE Office of Science User Facilities.

Along with the promise that CRISPR-Cas9 gene editing technology can offer new human therapies is the need to ensure its safety. A recent study showed that CRISPR-Cas9 did not produce off-target gene mutations in zebrafish. These results, published in Frontiers in Genetics, confirm previous data in animal models that the risk to the rest of the genome from gene editing is minimal.

"Our data add to a growing and important body of work from the scientific community that unintended mutations from gene editing with CRISPR-Cas9 are extremely rare," says senior author Nico Katsanis, PhD, Director of the Advanced Center for Translational and Genetic Medicine, Stanley Manne Children's Research Institute, at Ann & Robert H. Lurie Children's Hospital of Chicago. Dr. Katsanis also is Professor of Pediatrics and Cell and Molecular Biology at Northwestern University Feinberg School of Medicine. "These findings help to alleviate concerns about harmful errors when gene editing is used in humans. Our results provide reassurance that this technology is a valuable and valid tool with great promise for the treatment of genetic disorders."

CRISPR-Cas9 already is used in early stage clinical trials for cancer, sickle cell disease and childhood blindness. Currently, researchers remove cells from the body, edit the target gene and return it to the body.

Dr. Katsanis and colleagues performed whole exome sequencing (WES) in over 50 individual organisms from three generations of zebrafish, which allowed robust testing of gene editing effects. Zebrafish are a commonly used laboratory animal that share approximately 70 percent of its genome with humans. WES is used to identify genetic variants in portion of the genome that codes for proteins, and makes up the building blocks of cells, tissues and organs of the body.

"Although our study is just one of many recent reports, it is unique because we studied a large group of related animals that allowed us to screen for off-target effects in an unbiased way," says co-author Erica Davis, PhD, from the Advanced Center for Translational and Genetic Medicine, Manne Research Institute at Lurie Children's. Dr. Davis is Associate Professor of Pediatrics and Cell and Molecular Biology at Northwestern University Feinberg School of Medicine. "In addition to clinical implications, our results indicate that CRISPR-Cas9 is also a powerful research tool, helping us create new models of genetic disease with confidence."

Imagery from NASA-NOAA's Suomi NPP satellite showed that a tropical depression in the Arabian Sea has consolidated and organized despite facing wind shear. Tropical Depression 06A is now Tropical Cyclone 06A.

The Visible Infrared Imaging Radiometer Suite (VIIRS) instrument aboard Suomi NPP provided a visible image of 06A that revealed powerful storms were northwest of the center of circulation, but the storm was able to strengthen despite the harsh environmental conditions. The center of circulation is apparent in the VIIRS image as a small area of circulation located southeast of the bulk of clouds and showers.

In general, wind shear is a measure of how the speed and direction of winds change with altitude. Tropical cyclones are like rotating cylinders of winds. Each level needs to be stacked on top each other vertically in order for the storm to maintain strength or intensify. Wind shear occurs when winds at different levels of the atmosphere push against the rotating cylinder of winds, weakening the rotation by pushing it apart at different levels. In the case of Tropical Cyclone 06A, southeasterly winds are pushing the bulk of the storm's clouds to the northwest.

The Joint Typhoon Warning Center or JTWC in Pearl Harbor, Hawaii noted, "A fully exposed low level circulation center in animated multispectral satellite imagery. Strong (20-30 knot/ 23 to 34.5 mph /32 to 55.5 kph) vertical wind shear is offsetting good poleward outflow and warm (28 to 29 degrees Celsius/82.4 to 84.2 degrees Fahrenheit) sea surface temperature, hampering intensification." Tropical cyclones require sea surface temperatures of at least 26.6 degrees Celsius (80 degrees Fahrenheit) to maintain strength or intensify, so the warmer sea surface temperatures are allowing 06A to maintain its strength.

JTWC noted that at 10 a.m. EST (1500 UTC) on Dec. 3, that 06A had maximum sustained winds near 35 knots (40 mph/65 kph). 06A was located near latitude 7.1 degrees north and longitude 57.4 degrees east. It was about 784 nautical miles east-northeast of Mogadishu, Somalia.

It is moving to the northeast, however, and the track will slowly turn west southwestward as a subtropical ridge (elongated area of high pressure) builds back in to the north.

Tropical Cyclone 06A is forecast to make landfall in east central Somalia on Dec. 6 as a tropical storm.

Tropical cyclones and hurricanes are the most powerful weather events on Earth. NASA's expertise in space and scientific exploration contributes to essential services provided to the American people by other federal agencies, such as hurricane weather forecasting.

(BOSTON) -- We have a mutualistic but complicated relationship with the collection of microbes in our gut known as the intestinal microbiome. This complex community of bacteria breaks down different food components, and releases nutrients such as vitamins and a plethora of other factors that control functions in tissues way beyond the intestinal tract. However, the sheer numbers of microbes also present a threat as they can trigger inflammation, which is thought to be at the root of many intestinal diseases, including inflammatory bowel disease, radiation-induced intestinal injury, and some cancers.

To allow the uptake of beneficial substances from the gut lumen, and at the same time prevent gut microbes from contacting the intestinal epithelial tissue surface, specialized cells called goblet cells continuously produce mucus, the slimy goo-like substance that coats the entire intestinal surface. Mucus thus far has been notoriously difficult to study: its structure quickly disintegrates in surgically removed sections of the gut, the system most often used to study mucus, and no in vitro culture system has been able to reconstitute an in vivo-like mucus layer with the natural structure seen in living intestine outside the human body. Adding to these difficulties, mucus also differs between humans and other species, different sections of the intestinal tract, and even different individuals.

Now, focusing on the large intestine or colon which houses the greatest number of commensal microbes and has the thickest mucus layer, a team of tissue engineers at Harvard's Wyss Institute for Biologically Inspired Engineering has developed a colon-on-a-chip (Colon Chip) microfluidic culture device lined by patient-derived colon cells that spontaneously accumulates a mucus layer with the thickness, bi-layered structure, and barrier functions typically found in normal human colon. The mucosal surface in their model also responds to the inflammatory mediator prostaglandin E2 (PGE2) by mounting a rapid swelling response. Their findings are published in Cellular and Molecular Gastroenterology and Hepatology.

"Our approach provides researchers with the opportunity to find answers to questions about normal and disease-associated mucus biology, such as its contributions to intestinal inflammatory diseases and cancers, and complex host-microbiome interactions," said Founding Director Donald Ingber, M.D., Ph.D., who is the senior investigator on the study. "Importantly, we use patient-derived cells to line these devices and so this represents an entirely new approach for personalized medicine where it can be possible to study how mucus functions or dysfunctions in a particular patient, and to tailor therapy accordingly."

Ingber is also the Judah Folkman Professor of Vascular Biology at Harvard Medical School and the Vascular Biology Program at Boston Children's Hospital, as well as Professor of Bioengineering at Harvard's John A. Paulson School of Engineering and Applied Sciences. His team is part of a multi-institutional collaboration supported by a Cancer Research UK's Grand Challenge grant in which his Wyss team investigates how inflammation-related changes contribute to formation of cancers, including colon cancers. The Grand Challenge is an ambitious international cancer research initiative, supporting world-leading teams of scientists to take on some of the toughest challenges in cancer, and giving them the freedom to try novel approaches at scale.

The team's approach starts out with patient-derived colon cells from colon resections and endoscopic biopsies that are first grown as "organoids", tiny organized balls of colon tissue that contain mainly epithelial stem cells. After fragmenting the organoids, their cells are used to populate the upper of a two parallel channels of a microfluidic chip that are separated by a porous membrane. Simply by perfusing the channels continuously with nutrient medium, the colon stem cells grow into a continuous sheet and form highly functional goblet cells that secrete mucus.

"Growing the cells on-chip under flow results in about 15% of epithelial cells spontaneously differentiating into Goblet cells. Distributed throughout the epithelium, these produce an in vivo-like mucus layer," said first-author Alexandra Sontheimer-Phelps, a graduate student from the University of Freiburg, Germany, working in Ingber's group. "At the same time, other epithelial cells that keep dividing also replenish the Goblet cell population just like in living colon, which means that the chip can be maintained in steady-state conditions for more than two weeks, which makes it highly useful for longer-term studies."

The Wyss team showed that the colon epithelium in the chip is fully polarized with distinct markers restricted to its lumen-exposed, mucus-secreting side and its opposite membrane-binding side. Its goblet cells secrete the major mucus protein mucin 2 (MUC2), which when linked to complex chains of sugar molecules, assembles into multi-molecular network or gel that takes up water. "Our approach actually produces the bi-layered structure of normal colon mucus with an inner dense layer that we show is impenetrable to bacteria-mimicking particles flowed through the intestinal channel, and a more loose outer layer that allows particles to enter. This has never been accomplished before in vitro," said Sontheimer-Phelps.

To investigate the functionality of the mucus, she and her co-workers exposed the chip to the inflammatory mediator PGE2. The mucus underwent rapid swelling within minutes and independent of any new mucus secretion, and this process of mucus accumulation can be visualized in living cultures by viewing the chips from the side with dark field illumination. This dynamic response could be blocked by inhibiting one particular ion channel, which pumps ions into the colon epithelium and passively allow water molecules to follow and apparently, this drives mucus swelling when stimulated by signals such as PGE2.

Mucus has long been thought to be a passive, host barrier, but it is becoming increasingly clear that microbial species affect its structure and function in addition to feeding on its carbohydrates as an energy source. "Our in vitro system brings us one step closer to figuring out how individual bacterial species and more complex microbial communities can affect mucus and vice versa, as well as how this complex interplay impacts development of intestinal diseases. We also now have a testbed to discover new therapeutic drug and probiotic strategies that might prevent or reverse these diseases" said Ingber.

Metalenses -- flat surfaces that use nanostructures to focus light -- are poised to revolutionize everything from microscopy to cameras, sensors, and displays. But so far, most of the lenses have been about the size of a piece of glitter. While lenses this size work well for some applications, a larger lens is needed for low-light conditions, such as an imaging system onboard orbital satellites, and VR applications, where the lens needs to be larger than a pupil.

Now, researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have developed an all-glass, centimeter-scale metalens in the visible spectrum that can be manufactured using conventional chip fabrication methods.

The research was published in Nano Letters.

"This research paves the way for so-called wafer level cameras for cell phones, where the CMOS chip and the metalenses can be directly stacked on top of each other with easy optical alignment because they are both flat," said Federico Capasso, the Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering at SEAS and senior author of the paper. "In the future, the same company can make both the chip and the lenses because both can be made using the same technology: lithography."

"Previously, we were not able to achieve mass-production of centimeter-scale metalenses at visible wavelengths because we were either using electron-beam lithography, which is too time consuming, or a technique called i-line stepper lithography, which does not have enough resolution to pattern the required subwavelength-sized structures," said Joon-Suh Park, a Ph.D. candidate at SEAS and first author of the paper.

To mass produce a centimeter-scale metalens, the researchers used a technique called deep-ultraviolet (DUV) projection lithography, which is commonly used to pattern very fine lines and shapes in silicon chips in everything from computers to cell phones. The technique can produce many metalenses per chip, each made of millions of nanoscale elements with a single shot of exposure, like taking a photograph.

The researchers eliminated the time-consuming deposition processes that were required for previous metalenses by etching the nanostructure pattern directly onto a glass surface.

It is the first mass-producible, all-glass, centimeter-scale metalens in the visible spectrum.

While this lens is chromatic, meaning all the different colors of light don't focus at the same spot, the researchers are working on large-diameter achromatic metalenses.

New insight on how a type of cell facilitates the spread of HIV-1 has been published today in the open-access journal eLife.

The findings in mice suggest that subcapsular sinus macrophages, the first layer of cells in the draining lymph node, act as a kind of 'shuttle' for HIV-1 virus-like particles. These cells help the particles spread by loading them onto two types of immune cells, follicular dendritic cells and B cells.

HIV is a virus that damages immune cells and suppresses the host's ability to fight everyday infections and disease. During HIV-1 infection, follicular dendritic cells act as a reservoir for the virus and an obstacle to curative treatments, but it was not well known how these cells initially acquire and preserve HIV-1. Researchers from the National Institute of Allergy and Infectious Diseases (NIAID), part of the U.S. National Institutes of Health in Bethesda, Maryland, set out to investigate this further. The team consisted of John Kehrl, Chief of the B-cell Molecular Immunology Section of NIAID, and Chung Park, Staff Scientist in the same department.

In their study, Kehrl and Park visualised the likely early events in the spread of HIV-1 virus-like particles in mice. They looked at how the virus moves from the lymph and blood via sinus-lining macrophages, and how it is then transferred to underlying networks of follicular dendritic cells.

Their work highlighted a subset of lymphoid organ sinus-lining macrophages that provide a cell-to-cell contact portal to shuttle HIV-1 particles onto follicular dendritic and B cells in the lymph node and spleen. They found that a type of protein called MFG-E8 is central to the proper function of this portal, as its absence severely limited the spread of HIV-1 onto follicular dendritic cell networks.

The team also revealed that the HIV-1 envelope, which encloses the viral particle and helps the virus enter cells, provides a means for MFG-E8 binding. MFG-E8 acts to link the HIV-1 particles to αvβ3 integrins expressed on the host's cells. These integrins help the cell's uptake of the viral particles, making the particles available to other cell types or, in some instances, targeting them for destruction. Kehrl and Park say that further work is now needed to see whether this process involving MFG-E8 works to benefit the host or the virus.