Tech

What started out as a hunt for ice lurking in polar lunar craters turned into an unexpected finding that could help clear some muddy history about the Moon's formation.

Team members of the Miniature Radio Frequency (Mini-RF) instrument on NASA's Lunar Reconnaissance Orbiter (LRO) spacecraft found new evidence that the Moon's subsurface might be richer in metals, like iron and titanium, than researchers thought. That finding, published July 1 in Earth and Planetary Science Letters, could aid in drawing a clearer connection between Earth and the Moon.

"The LRO mission and its radar instrument continue to surprise us with new insights about the origins and complexity of our nearest neighbor," said Wes Patterson, Mini-RF principal investigator from the Johns Hopkins Applied Physics Laboratory (APL) in Laurel, Maryland, and a study coauthor.

Substantial evidence points to the Moon as the product of a collision between a Mars-sized protoplanet and young Earth, forming from the gravitational collapse of the remaining cloud of debris. Consequently, the Moon's bulk chemical composition closely resembles that of Earth.

Look in detail at the Moon's chemical composition, however, and that story turns murky. For example, in the bright plains of the Moon's surface, called the lunar highlands, rocks contain smaller amounts of metal-bearing minerals relative to Earth. That finding might be explained if Earth had fully differentiated into a core, mantle and crust before the impact, leaving the Moon largely metal-poor. But turn to the Moon's maria -- the large, darker plains -- and the metal abundance becomes richer than that of many rocks on Earth.

This discrepancy has puzzled scientists, leading to numerous questions and hypotheses regarding how much the impacting protoplanet may have contributed to the differences. The Mini-RF team found a curious pattern that could lead to an answer.

Using Mini-RF, the researchers sought to measure an electrical property within lunar soil piled on crater floors in the Moon's northern hemisphere. This electrical property is known as the dielectric constant, a number that compares the relative abilities of a material and the vacuum of space to transmit electric fields, and could help locate ice lurking in the crater shadows. The team, however, noticed this property increasing with crater size.

For craters approximately 1 to 3 miles (2 to 5 kilometers) wide, the dielectric constant of the material steadily increased as the craters grew larger, but for craters 3 to 12 miles (5 to 20 kilometers) wide, the property remained constant.

"It was a surprising relationship that we had no reason to believe would exist," said Essam Heggy, coinvestigator of the Mini-RF experiments from the University of Southern California in Los Angeles and lead author of the published paper.

Discovery of this pattern opened a door to a new possibility. Because meteors that form larger craters also dig deeper into the Moon's subsurface, the team reasoned that the increasing dielectric constant of the dust in larger craters could be the result of meteors excavating iron and titanium oxides that lie below the surface. Dielectric properties are directly linked to the concentration of these metal minerals.

If their hypothesis were true, it would mean only the first few hundred meters of the Moon's surface is scant in iron and titanium oxides, but below the surface, there's a steady increase to a rich and unexpected bonanza.

Comparing crater floor radar images from Mini-RF with metal oxide maps from the LRO Wide-Angle Camera, Japan's Kaguya mission and NASA's Lunar Prospector spacecraft, the team found exactly what it had suspected. The larger craters, with their increased dielectric material, were also richer in metals, suggesting that more iron and titanium oxides had been excavated from the depths of 0.3 to 1 mile (0.5 to 2 kilometers) than from the upper 0.1 to 0.3 miles (0.2 to 0.5 kilometers) of the lunar subsurface.

"This exciting result from Mini-RF shows that even after 11 years in operation at the Moon, we are still making new discoveries about the ancient history of our nearest neighbor," said Noah Petro, the LRO project scientist at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "The MINI-RF data is incredibly valuable for telling us about the properties of the lunar surface, but we use that data to infer what was happening over 4.5 billion years ago!"

These results follow recent evidence from NASA's Gravity Recovery and Interior Laboratory (GRAIL) mission that suggests a significant mass of dense material exists just a few tens to hundreds of kilometers beneath the Moon's enormous South Pole-Aitken basin, indicating that dense materials aren't uniformly distributed in the Moon's subsurface.

The team emphasizes that the new study can't directly answer the outstanding questions about the Moon's formation, but it does reduce the uncertainty in the distribution of iron and titanium oxides in the lunar subsurface and provide critical evidence needed to better understand the Moon's formation and its connection to Earth.

"It really raises the question of what this means for our previous formation hypotheses," Heggy said.

Anxious to uncover more, the researchers have already started examining crater floors in the Moon's southern hemisphere to see if the same trends exist there.

July 1, 2020--More research must be done to investigate the role of air pollution on the epigenome in patients with interstitial lung diseases (ILDs), in order to develop strategies that minimize the effects of these pollutants, according to a new article published online in the American Thoracic Society's American Journal of Respiratory and Critical Care Medicine.

ILDs are a group of serious respiratory diseases, the most common of which is idiopathic pulmonary fibrosis (IPF), which cause scarring of lung tissue. The epigenome consists of chemical compounds and proteins that attach themselves to DNA to regulate its functions and influence which genes are being turned "on" or "off." Environmental exposures like air pollution play a critical role in modifying epigenetic factors, which is one way these exposures may contribute to disease development.

In "Air Pollution and Interstitial Lung Disease: Defining Epigenomic Effects," Gillian C. Goobie, MD, and co-authors review research on the effects of air pollution on ILD and other respiratory diseases, the current state of knowledge about the epigenome in ILD, and how epigenetic methods may be applied to understand the impact of air pollution on patients with ILD.

"We are still in the early stages of defining air pollution as a clinical risk factor, and this is an area that requires further validation before subsequent mechanistic studies can be fully pursued," said Dr. Goobie, PhD student, Department of Human Genetics, Graduate School of Public Health, University of Pittsburgh. "In order to quantify the impact that changes to the epigenome as a result of air pollution exposure have on the development of ILD and adverse outcomes in these conditions, we first need to have robust effect estimates derived from clinical research."

Dr. Goobie believes that, "We are just coming to the point where these effect estimates are well-defined enough, specifically in idiopathic pulmonary fibrosis (IPF), to apply this knowledge to more molecular and mechanistic studies. There is still a huge gap in the clinical research domain defining the impact of air pollution on other non-IPF forms of ILD."

The effects of air pollution on chronic obstructive pulmonary disease (COPD) and asthma are well established, however, the impact on patients with ILD is not well understood. While scientists know that occupational and environmental pollutant exposures contribute to the development and progression of ILD, the mechanisms are not clearly defined.

The authors reviewed the scientific literature on associations between exposure to air pollution and negative health effects on people with ILD. One study of healthy individuals, for example, found that long-term exposure to nitrogen dioxide was associated with higher odds of developing interstitial lung abnormalities (ILA), which are precursors to full-blown ILD. Another study of healthy individuals found that long-term elemental carbon exposure was associated with increased odds of developing ILA and ILA progression. Although further study is needed, other pollutants that may be involved in ILD include fine particulates, ozone, and nitrogen dioxide.

The authors looked at a number of studies that show a relationship between asthma, COPD and air pollution on a molecular level. They go on to discuss the steps necessary before such research on ILA and ILD can become a reality, and the complications involved in doing such research on a group of related diseases, as ILDs are more than 200 distinct diseases. They also discuss the limitations of epigenetic research on lung diseases to date. Dr. Goobie and colleagues elucidate the necessary preliminary steps in epigenetic research on ILD which include, for example, clarifying the relationship between epigenetic patterns in peripheral blood and lung tissue. These types of studies will enable researchers to explore how these patterns vary with air pollution exposure.

"I see air pollution as one of the most substantial public health and environmental crises facing the globe today," noted Dr. Goobie. "Not only is it responsible for millions of premature deaths annually, but these deaths disproportionately affect individuals of lower socioeconomic status and minority race. It is imperative that physicians and scientists dive into the mechanistic underpinnings associating air pollution with chronic disease. This is especially important in chronic diseases with high mortality and unclear pathophysiology, such as ILDs, where pollution exposure may play a significant role in disease development and progression. I believe that this area of research is important not only for disease prevention, but also for promoting environmental justice and health equity."

Dr. Goobie and colleagues conclude, "Air pollution has been associated with pre-clinical interstitial lung disease as well as increased incidence, acute exacerbation rate, lung function decline, and mortality in patients with IPF, the most common form of ILD. Despite these convincing findings, there has been minimal investigation of the molecular mechanisms in which air pollution may trigger ILD development and progression. Learning from prior studies of genome-epigenome-environment interactions in other chronic respiratory diseases, we can adapt these methodologies to investigate the impact of air pollution in patients with ILD. This is an especially prescient avenue for research given the increasing burden of air pollution across the U.S., as well as the increasing global burden of mortality from ILD and our lack of understanding about common environmental risk factors leading to the development of these devastating diseases."

hat can be processed at temperatures low enough to allow plastics to be coated. The team published their report in the journal Small, where it was featured as the cover story in the edition from 4 June 2020.

The application of zinc oxide layers in industry is manifold and ranges from the protection of degradable goods to the detection of toxic nitrogen oxide gas. Such layers can be deposited by atomic layer deposition (ALD) which employs typically chemical compounds, or simply precursors, which ignite immediately upon contact with air, i.e. are highly pyrophoric. An interdisciplinary research team at Ruhr-Universität Bochum (RUB) has now established a new fabrication process based on a non-pyrophoric zinc precursor that can be processed at temperatures low enough to allow plastics to be coated. The team published their report in the journal Small, where it was featured as the cover story in the edition from 4 June 2020.

Depositing ultra-thin layers

In order to produce a sensor for nitrogen dioxide (NO2), a thin layer of nanostructured zinc oxide (ZnO) must be applied to a sensor substrate and then integrated into an electrical component. Professor Anjana Devi's team used ALD to apply ultra-thin ZnO layers on such sensor substrates.

In general, ALD processes are used in industry to miniaturise electrical components using ultra-thin layers, some of which are only a few atomic layers thick, while at the same time increasing their efficiency. For that, suitable precursors are required that react at surfaces to form such a thin film. "The chemistry behind ALD processes is therefore essential and has a huge impact on the resulting thin films," points out Anjana Devi.

Safe handling and highest quality

To date, industrial manufacturers have been producing ZnO thin films by deploying an extremely reactive, highly pyrophoric zinc precursor via ALD. "The key for the development of a safe alternative ALD process for ZnO at RUB was to develop a new, non-pyrophoric precursor that is safe to handle and is able to deposit ZnO thin films of the highest quality," explains Lukas Mai, lead author of the study. "The challenge was to find alternative chemistries to replace the pyrophoric compounds that are generally used in the industry for ZnO."

The unique aspect of the new process is that it can be performed at very low process temperatures, thus facilitating deposition onto plastics. Consequently, the new process can be used not only for the manufacture of gas sensors, but also of gas barrier layers. In the packaging industry, such layers are applied on plastics to protect degradable goods such as food or pharmaceuticals from air.

Study Gains New Insight Into Bacterial DNA Packing
By Julie Chao

When bacteria are put in different environments, such as one that is more acidic or anaerobic, their genes start to adapt remarkably quickly. They're able to do so because the proteins making up their chromosome can pack and unpack rapidly. Now, a Berkeley Lab-led team of researchers has been able to capture this process at the molecular level using advanced imaging techniques, a discovery that could eventually enable scientists to develop strategies to control microbial behavior.

The researchers used multiple high-powered X-ray techniques at Berkeley Lab's Advanced Light Source (ALS), a Department of Energy Office of Science user facility, to image the process in E. coli bacteria at the micro-, meso-, and nanoscales. The imaging technique they developed enabled them to visualize the bacteria's chromosome at higher resolutions than ever before, and without the need for labeling, which slows down the process but is required by most other techniques. Their study was published recently in the journal Nature Communications.

"We now understand how the packing of the DNA is controlled by the DNA binding proteins, called HU, interacting with each other," said Michal Hammel, the corresponding author of the paper and a research scientist in Berkeley Lab's Molecular Biophysics and Integrated Bioimaging (MBIB) Division. "So now we can try to figure out how to control it, how to inhibit or accelerate the packing of the DNA. If you can change packing of DNA, you can change bacterial behavior; then you can start developing alternative approaches to fighting bacterial infections."

The team included Carolyn Larabell, MBIB faculty scientist and director of the National Center for X-Ray Tomography at the ALS, and the lead authors were Soumya Govinda Remesh and Subhash Verma of the National Cancer Institute.

New Synthetic Biology Tools Unlock Complex Plant Engineering
By Emily Scott

Researchers at JBEI have developed a new set of synthetic biology tools that could unlock advanced plant engineering.

The ability to genetically engineer plants is key for creating sustainable agriculture and renewable energy. But the methods currently used to engineer plants are underdeveloped compared to those for bacteria, limiting scientists in their ability to add preferable traits or delete unwanted ones.

To meet this need, researchers at the Joint BioEnergy Institute (JBEI) developed a set of synthetic plant promoters -- which are required for a gene to be expressed in a plant -- that will help scientists engineer more sophisticated traits in plants. Their work, led by Patrick Shih, is published in Nature Chemical Biology.

Shih, director of Plant Biosystems Design at JBEI, said this research provides a proof of concept that plant promoters can be tailor-made to achieve a specific gene expression pattern.

"There's a lot of excitement in the field there. We've been stuck with using whatever promoters already exist," Shih said. "If we can design them from scratch, it allows us to not only engineer various traits into plants, but it also opens up the window to study plant biology in a whole different way using synthetic biology."

These new synthetic promoters allow scientists to control how much or how little a gene is expressed, providing more control. They also allow for genes to be expressed in a specific part of the plant, such as the roots or the leaves. These functionalities have previously been challenging to achieve.

"The ability to design and build custom-made promoters now gives us the flexibility to go after different targets and applications," Shih said. "It opens the door to really sophisticated synthetic biology efforts in the future."

JBEI is a DOE Bioenergy Research Center supported by DOE's Office of Science.

High-Performance Windows to Benefit Low-Income California Communities
By Kiran Julin

Buildings account for a whopping 40% of total U.S. energy consumption, and windows are responsible for approximately 10% of that. High thermal performance windows reduce combined heating and cooling energy consumption of typical single family homes in California by up to 50% compared to existing single-pane windows, which are still found in 6.5 million, or 50%, of homes in California.

A $1.85 million grant by the California Energy Commission's (CEC's) Electric Program Investment Charge was recently awarded to Berkeley Lab to install energy-saving, thin-glass triple-pane windows in low-income communities in California. Thanks to years of investment and support from the CEC and the Department of Energy (DOE), Berkeley Lab researchers will work with industry partners to retrofit these high-performance windows into two multi-family buildings, each with eight tenant units, and 30 single-family housing units, all located in low-income California communities.

"By partnering with building and window manufacturers, including Cornerstone Building Brands, we hope that this demonstration project will remove barriers to the development and widespread adoption of highly insulating window technologies in the retrofit and new construction markets," said Berkeley Lab Principal Scientific Engineering Associate Robert Hart, who is the lead researcher on highly insulating windows. "With more widespread adoption, energy-efficient technologies such as thin-triple windows, can become even more affordable and accessible."

For more, click here.

For more background on these windows, click here .

Ultrafine Control: Researchers Discover Ferroelectricity at the Atomic Scale
By Theresa Duque

A team of researchers led by Sayeef Salahuddin , faculty scientist in Berkeley Lab's Materials Sciences Division and professor of electrical engineering and computer sciences at UC Berkeley, has managed to grow onto silicon an ultrathin material that demonstrates a unique electrical property called ferroelectricity. Their findings were published in the journal Nature .

Ferroelectricity refers to a class of materials that can not only achieve spontaneous electric polarization, but also reverse the direction of polarization when exposed to an external electric field, which is promising for electronics.

Although researchers had previously stabilized ferroelectricity in ultrathin materials, past studies observed that ferroelectricity diminishes in conventional ferroelectric materials thinner than around 3 nanometers (3 billionths of a meter).

The Berkeley Lab-led team's breakthrough reported in the current study demonstrates that ferroelectric effects can be enhanced in a material just 1 nanometer thick. As a result, the material - when engineered into a logical storage or switching device - can efficiently control the smallest devices with lower amounts of energy.

The finding could lead to the creation of more advanced batteries and sensors. But the work is "especially relevant to next-generation low-power microelectronics," said co-author Jim Ciston, a staff scientist at the Molecular Foundry who led the electron microscopy portion of the project.

The material's structural characteristics were confirmed using transmission electron microscopy at Berkeley Lab's Molecular Foundry .

At Berkeley Lab's Advanced Light Source, the researchers employed sophisticated X-ray absorption spectroscopy, X-ray linear dichroism, and photoemission electron microscopy techniques to explore the material's structural and electronic origins of ferroelectricity.
In 2019, Ciston was one of 315 researchers selected to receive the prestigious Presidential Early Career Award for scientists and engineers, which partially funded his work on the study.

Adapted from a news release by Thomas Lee, UC Berkeley, School of Engineering

A radar signature may help distinguish which severe storms are likely to produce dangerous tornadoes, potentially leading to more accurate warnings, according to scientists.

"Identifying which storms are going to produce tornadoes and which are not has been a problem meteorologists have been trying to tackle for decades," said Scott Loeffler, a graduate student in the Department of Meteorology and Atmospheric Science at Penn State. "This new research may give forecasters another tool in their toolbox to do just that."

Scientists analyzed radar data from more than a hundred supercell thunderstorms, the most prolific producers of violent tornadoes, and found a statistically significant difference in the structure of storms that produced a tornado and those that did not.

Weather radar constantly monitors storms across the country, and data similar to that used in the study are readily available to operational forecasters who issue warnings, the scientists note.

"These findings have potentially large implications for the accuracy and confidence of tornado warnings and public safety during severe storms," said Matthew Kumjian, associate professor of meteorology at Penn State and Loeffler's adviser. "We look forward to getting this information in the hands of operational meteorologists to assess the impact it has."

Tornado warning times have improved over the last several decades, thanks in part to numerical modeling research and intensive field campaigns, but decision-makers often must rely on readily available information like radar data when issuing storm warnings, the scientists said. Previous efforts using conventional radar have struggled to distinguish between tornadic and nontornadic supercells.

According to the researchers, in 2013, the U.S. upgraded its radar network to include polarimetric capabilities, which provide additional information about storms, including revealing the shape and size of raindrops.

Using this information, the scientists compared areas with large, sparse raindrops and regions dense with smaller drops within supercell storms. The orientation of these two areas was significantly different in tornadic and nontornadic supercells, the researchers reported in the journal Geophysical Research Letters.

"We found for nontornadic supercells, the orientation of the separation between these two areas tended to be more parallel to the direction of the storm's motion," Loeffler said. "And for tornadic supercells, the separation tended to be more perpendicular. So we saw this shift in the angles, and we saw this as a consistent trend."

Loeffler said the algorithm from the study can easily be adapted so operational forecasters could use the program in real time with the latest radar data available.

"Many factors go into issuing a tornado warning, but perhaps knowing the orientation in real time could help them make a decision to pull the trigger or to hold off," he said.

The scientists said while the signatures are promising, further numerical modeling studies are needed to understand better the relationship between the orientations and tornado formation.

Michael Jurewicz, a meteorologist with the National Weather Service and Michael French, assistant professor at Stony Brook University, contributed to the study.

A new thermoplastic biomaterial, which is tough and strong but also easy to process and shape has been developed by researchers at the University of Birmingham.

A type of nylon, the material's shape memory properties enable it to be stretched and moulded but able to reform into its original shape when heated. This makes it useful for medical devices such as bone replacements, where minimally invasive surgery techniques require additional flexibility in implant materials.

The material was developed in the University's School of Chemistry, by a team investigating ways to use stereochemistry - a double bond in the backbone of the polymer chain - to manipulate the properties of polyesters and polyamides (nylons). The study is published in Nature Communications.

Biocompatible polymers are widely used in medicine, from tissue engineering to medical devices such as stents and sutures. Although much progress has been made in the area of resorbable or degradable materials, that are broken down by the body over time, there are still only a handful of non-resorbable polymers that can be used for longer-term applications.

Existing non-resorbable biomaterials, like nylons, currently commercially available suffer from a variety of limitations. Metal implants, for example, can wear poorly, leading to particle fragments breaking off, while composite materials can be difficult to process or extremely expensive.

The new material can be made using standard chemistry techniques and offers a stable, long-lasting option, with mechanical properties that can be tuned for different end products.

Senior researcher, Professor Andrew Dove, says: "This material offers some really distinctive advantages over existing products used to manufacture medical devices such as bone and joint replacements. We think it could offer a cost-effective, versatile and robust alternative in the medical device marketplace."

A further advantage of the material is its amorphous structure. Josh Worch, the postdoctoral researcher who led the work, explains why: "For many plastics, including nylon, the toughness is often dependent on their semi-crystalline structure, but this also makes them harder to shape and mould. However, our new plastic is as tough as nylon, but without being crystalline so it is much easier to manipulate. We believe this is only possible due to the way we have used stereochemistry to control our design."

The research team were able to design and produce the plastic, which is now covered by a patent, and test it in rats to prove its biocompatibility. The team now plan to explore further ways to fine tune the material and its properties before seeking a commercial partner.

When it comes to nifty farm gadgets and technology, there are many neat tools. Tractor guidance is definitely one of them, thanks to how it helps farmers better use their resources.

Tractor guidance allows farmers to be more precise when using a tractor to perform tasks in the field. These tasks include planting, spraying herbicide, and applying fertilizer. But how does this precision turn into savings for a farmer?

Amanda Ashworth of the United States Department of Agriculture's Agricultural Research Service and a team of researchers worked to find out. Their results point to benefits for small farms, many of which do not currently use this tool.

"Precision agriculture technologies improved the on-farm efficiencies by up to 20% based on our work," Ashworth says. "There is a lot of room for more adoption of the technology on small farms. This would possibly lead to economic and environmental savings."

A farmer in a tractor makes a series of passes across a field to plant seeds or spray chemicals. Anywhere there is overlap in these passes is inefficient because it's an unnecessary double application. In addition to overlap, gaps of the field not covered in passes are also bad. It's a missed opportunity to improve crop production.

Tractor guidance uses GPS to help reduce these overlaps and gaps. It also allows researchers to track and record tractor movements. The researchers helped improve an existing calculation to best measure these overlaps and gaps. It particularly helped where the tractor turns around at the end of a row.

The team's results suggest that tractor guidance reduces overlaps by up to 6% and gaps by up to 16%. Farmer's profits are made on small margins, so a small decrease in fertilizer costs, for example, can be very beneficial. Also, fertilizer that runs off a field can harm waterways, so being able to apply just the correct amount can benefit the environment.

While many large crop producers use tractor guidance, they only make up about one fifth of farms in the United States. The rest are small farms. These smaller farms are often slower to learn about and adapt to these new technologies.

All combined, increases in efficiencies with tractor guidance on small farms could result in saving U.S. producers more than $10 million.

The precision tool has other benefits, too, such as letting drivers operate in low light to get more work done during the evening.

"Not all agricultural areas receive information on technology at the same rate, so there is work to be done here," explains Ashworth. "The small farm systems have high potential for adoption, which would impact the greatest numbers of farms."

The team's new method for calculating the benefits of tractor guidance can be easily used on many small fields to gather more data. Their hope is that it can help more famers learn about and adopt the tool since it can pay for itself - even on small farms.

Next, the researchers want to understand how field slope and objects in the way, such as trees or ponds, affect tractor guidance.

"Agriculture is moving toward using more technology for farm management decisions," Ashworth says. "We want to get a better understanding of current technology applications and how well they work. This will help us have a better idea of how to improve, develop, and integrate different components for improved production efficiency."

WASHINGTON, June 30, 2020 -- Mathematicians based in Australia and China have developed a method to analyze the large amount of data accumulated during the COVID-19 pandemic. The technique, described in the journal Chaos, by AIP Publishing, can identify anomalous countries -- those that are more successful than expected at responding to the pandemic and those that are particularly unsuccessful.

The data comes from Our World in Data, a project of the Global Change Data Lab, a registered charity in England and Wales. This organization collected information from the European Centre for Disease Prevention and Control for cumulative daily case counts and deaths for 208 countries over a period of 122 days from Dec. 31, 2019, to April 30, 2020. The investigators analyzed the data with a variation of a statistical technique known as a cluster analysis.

In this approach, data points are grouped according to similarity. The countries form clusters as individual outbreaks become more similar.

For all of January, the investigators found only two clusters: China in one cluster, and all the other 207 countries in the other. As the virus spread, additional countries jumped into the China cluster. Italy was the first to join, followed by the U.S., Spain, France, Germany, Iran and the U.K.

By mid-March, case counts for countries around the world grouped into 16 clusters. By April, a similar grouping was seen in death counts. In mid-March, China moved out of the worst death cluster, while the U.S., Spain, Italy, France and the U.K. moved into it.

The investigators found a notable break in the cluster structure for cases between March 1 and March 2. This date is significant, because numerous countries reported their first COVID-19 cases at that time, mostly coming from Iran and Italy.

Another break in the cluster structure occurs between March 18 and March 19 for deaths, a 17-day difference from that of cases. This offset suggests a 17-day lag for deaths behind cases and agrees with medical data.

Once the investigators identified the 17-day offset between cases and deaths, they were able to compare countries' case and death numbers at the same point in time. This revealed countries with anomalous results.

"Anomalies may signify either disproportionately high or low number of deaths relative to the number of cases," said co-author Nick James.

Iran and Italy both had anomalously high death rates early in the pandemic, while Singapore was anomalously low, as were South Korea, Qatar and Australia.

"We also noticed a sort of critical mass effect in the progression of cases to deaths," said co-author Max Menzies. "Spain's death count as of March 28 was over twice that of its case count just 16 days earlier. This is an astonishing explosion of COVID-19. It also applies to the U.S. Its dramatic elevation in death count hit after the case count reached a critical mass in early March."

Roadside hedges take a hit to their health while reducing pollution exposure for humans, a new study from the University of Surrey finds.

According to the European Environmental Agency, air pollution causes 400,000 premature deaths annually. In 2017, the Department for Environment, Food and Rural Affairs pinpointed pollution generated by traffic as a major contributor of particulate matter.

In a new study published by Environmental Pollution, experts from Surrey's Global Centre for Clean Air Research (GCARE) set out to quantify the deposition of particles on leaf surfaces of a roadside hedge at child (0.6m) and adult (1.5m) breathing heights.

The study, titled 'Quantifying particulate matter reduction and their deposition on the leaves of green infrastructure', examined a beech (Fagus sylvatica) hedge along a busy two-lane road in Guildford, Surrey. They also monitored a nearby location on the same road with no hedge.

Following previous work by GCARE researchers to quantify the filtering capacity of different types of green infrastructure, including roadside hedges, this new study involved quantifying and comparing particle deposition on leaves from the front (traffic-facing) and back side of a hedge.

The researchers discovered a dominance of fine particles on leaves on the traffic-facing side when compared with the back of the hedge. They also found that the closer the hedge is to road, it likely led to the underdevelopment and poor heath of leaves on the traffic-facing side of the hedge.

The team discovered that more harmful particles were captured by leaves at child breathing height than at adult breathing height, supporting GCARE's previous studies on how air pollution is harming babies who travel in low-riding prams more than it is affecting the parents pushing them.

The researchers also found that leaf fall in autumn lowered the canopy density, resulting in particulate matter reductions behind the hedge to drop from 25 percent in summer to 9 percent in autumn.

Professor Prashant Kumar, Director of GCARE at the University of Surrey, said: "The poor health of leaves on the traffic-facing side highlights that green infrastructure takes a continuous assault from traffic emissions to protect roadside users from harmful sub-micron particles."

"The high particle capture during peak traffic hours at around the breathing height of children compared with adult breathing height reinforces our advocacy for the implementation of hedges as a barrier against traffic emissions, particularly around school boundaries, children's play areas, and other vulnerable populations. This study's findings also underline the importance of appropriate selection of vegetation species considering traits such as air pollution tolerance."

Researchers from the Institute of Process Engineering (IPE) of the Chinese Academy of Sciences and Argonne National Laboratory (Argonne) in the U.S. have recently employed atomic layer deposition (ALD) to fabricate visible light-activated membranes that efficiently utilize solar energy.

The study was published in Advanced Functional Materials on June 30.

This research is important because membranes are among the most promising means of delivering increased supplies of fit-for-purpose water. However, membrane fouling remains a critical issue restricting their widespread application.

The modified membrane in this study exhibits outstanding antifouling and in situ self-cleaning performance under visible light irradiation.

Coupling photocatalysis with membrane separation has previously been proposed as a potentially effective way to reduce membrane fouling. However, materials used in photocatalysis limit the use of low-cost sources such as sunlight due to their large bandgaps.

To solve this problem, the researchers fabricated a visible light-activated photocatalytic film by doping nitrogen into the lattice of TiO2 deposited on commercial ceramic membranes using ALD.

The N-TiO2 coating endowed membranes with a capacity for effective in situ self-cleaning and enhanced stability under solar irradiation owing to the redox reactions between organic foulants and generated reactive oxygen species (ROS) as well as the increase in surface hydrophilicity.

The synergy between membrane separation and redox reactions involving organic pollutants and ROS produced by the visible light-activated layer suggests a possibility for stable and sustainable membrane operation under in situ solar irradiation.

The researchers also highlighted the importance of ALD technology in fabricating the membranes.

Prof. LUO Jianquan from IPE said that the study "opens a door" to applying ALD technology to membrane surface modification for fouling control.

Seth B. Darling, a co-author from Argonne, noted that the current research is "among the first successful demonstrations of real-time self-cleaning of a membrane during operation." He also said that ALD is a powerful tool for improving the performance of membrane separations beyond fouling mitigation.

N-doped photocatalytic films and ALD offer promise for using solar energy to effectively control membrane fouling and for establishing a sustainable membrane separation system.

By introducing fluorescence protein sensors into live plants, a novel method that allows in planta measurement of NADPH level and NADH/NAD+ ratio in different cell types has been developed. These transgenic lines enable scientists to visualize the dynamic changes of these molecules in different subcellular compartments in real-time, to study photosynthesis and photorespiration.

Plants harvest energy from the sun and use this to fix CO2 from the atmosphere to produce complex organic molecules which are the basis for life on the earth. The process of photosynthesis takes place in leaves and other green parts of the plant where chloroplasts are main players of the process but the whole cell is involved. In plants, the shift between respiratory metabolism in the dark and photosynthetic metabolism in the light makes redox control of metabolism particularly complex. For an efficient process the redox states of all cellular compartments must be coordinated but is has been very difficult to obtain In planta data on this important aspect.

During C3 photosynthesis, for every 3 fixed CO2 molecules, about one O2 molecule is mistakenly fixed by Rubisco in chloroplasts. The recycling of the photorespiratory product involves reactions in both chloroplasts, peroxisomes and mitochondria. In connection to this it is commonly agreed that redox transfer between the compartments involved is important and that malate-OAA exchange contributes to this. However, the redox balance between the compartments is not well established and several suggestions can be found in the literature.

To study this question, an international team of researchers led by Dr. Boon Leong Lim of the School of Biological Sciences of the University of Hong Kong adopted fluorescent protein sensors to specifically monitor in planta dynamic changes in NADPH and NADH/NAD+ ratio in young leaves. The redox states of chloroplasts, cytosol and peroxisomes could be followed during transitions between dark and light with an emphasis on interplay between photosynthesis and photorespiration. Conventional detection methods require extraction and purification of these redox metabolites and subsequent determination by chemical methods. These methods have a few drawbacks as they are incapable of real-time, in planta measurements, nor measurement of these molecules in different cell types or different subcellular compartments. “Our novel technique can circumvent all of these problems. By employing these novel fluorescent protein sensors, we found that photorespiration supplies a large amount of NADH to mitochondria during photosynthesis, which exceeds the NADH-dissipating capacity of the mitochondrial respiratory chain. Consequently, the surplus NADH must be exported from the mitochondria to the cytosol through the mitochondrial malate-OAA shuttle. (Figure)”, said Ms. Sheyli Lim, a PhD student and the first author of a manuscript published in Nature Communications. “Solving this question allows us to understand more about the energy flow between chloroplasts and mitochondria during photosynthesis, which could help us to booth the efficiency of photosynthesis in the future”.

“The ability to get in vivo estimations on subcellular redox states gives important novel information on regulation of plant metabolism. The results highlight the close connection between the different subcellular compartments to achieve an efficient process. I have for a long time been studying the mitochondrial contribution to photosynthetic metabolism so for me this aspect has been most interesting” said co-author Prof. Per Gardeström of Umeå University.

Dr. Lim added: “We are the first group to introduce these three novel energy (ATP, NADPH, NADH/NAD+) sensors in plants. I wish they will have wide applications in researches regarding plant bioenergetics.”.

Steering and monitoring the light-driven motion of electrons inside matter on the time-scale of a single optical cycle is a key challenge in ultrafast light wave electronics and laser-based material processing. Physicists from the Max Born Institute in Berlin and the University of Rostock have now revealed a so-far overlooked nonlinear optical mechanism that emerges from the light-induced tunneling of electrons inside dielectrics. For intensities near the material damage threshold, the nonlinear current arising during tunneling becomes the dominant source of bright bursts of light, which are low-order harmonics of the incident radiation. These findings, which have just been published in Nature Physics, significantly expand both the fundamental understanding of optical non-linearity in dielectric materials and its potential for applications in information processing and light-based material processing.

Our current understanding of non-linear optics at moderate light intensities is based on the so-called Kerr non-linearity, which describes the non-linear displacement of tightly bound electrons under the influence of an incident optical light field. This picture changes dramatically when the intensity of this light field is sufficiently high to eject bound electrons from their ground state. At long wavelengths of the incident light field, this scenario is associated with the phenomenon of tunneling, a quantum process where an electron performs a classically forbidden transit through a barrier formed by the combined action of the light force and the atomic potential.

Already since the 1990's and pioneered by studies from the Canadian scientist François Brunel, the motion of electrons that have emerged at the "end of the tunnel", which happens with maximal probability at the crest of the light wave, has been considered as an important source for optical non-linearity. This picture has now changed fundamentally. "In the new experiment on glass, we could show that the current associated with the quantum mechanical tunneling process itself creates an optical non-linearity that surpasses the traditional Brunel mechanism", explains Dr. Alexandre Mermillod-Blondin from the Max Born Institute for Nonlinear Optics and Short Pulse Spectroscopy, who supervised the experiment. In the experiment, two ultrashort light pulses with different wavelengths and slightly different propagation directions were focused onto a thin slab of glass, and a time- and frequency-resolved analysis of the emerging light emission was performed.

Identification of the mechanism responsible for this emission was made possible by a theoretical analysis of the measurements that was performed by the group of Prof. Thomas Fennel, who works at the University of Rostock and at the Max Born Institute in the framework of a DFG Heisenberg Professorship. "The analysis of the measured signals in terms of a quantity that we termed the effective non-linearity was key to distinguish the new ionization current mechanism from other possible mechanisms and to demonstrate its dominance", explains Fennel.

Future studies using this knowledge and the novel metrology method that was developed in the course of this work may enable researchers to temporally resolve and steer strong-field ionization and avalanching in dielectric materials with unprecedented resolution, ultimately possibly on the time-scale of a single cycle of light.

Healing broken bones could get easier with a device that provides both a scaffold for the bone to grow on and electrical stimulation to urge it forward, UConn engineers reported on June 27 in the Journal of Nano Energy.

Although minor bone breaks usually heal on their own, large fractures with shattered or missing chunks of bone are more difficult to repair. Applying a tiny electrical field to the site of the fracture to mimic the body's natural electrical field helps the cells regenerate. But the medical devices that do this are usually bulky, rely on electrical wires or toxic batteries, require invasive removal surgery, and can't do much for serious injuries.

Now, a group of biomedical engineers from UConn have developed a scaffold of non-toxic polymer that also generates a controllable electrical field to encourage bone growth. The scaffold helps the body bridge large fractures. Although many scientists are exploring the use of scaffolding to encourage bone growth, pairing it with electrical stimulation is new.

The team demonstrated the device in mice with skull fractures.

The electrical voltage the scaffold generates is very small, just a few millivolts. And uniquely for this type of device, the voltage is generated via remotely-controlled ultrasound. The ultrasound vibrates the polymer scaffolding, which then creates an electrical field (materials that create electricity from vibration, or vice versa, are called piezoelectric.) To help heal a thigh fracture, for example, the polymer scaffold can be implanted across the broken bone. Later, the person with the broken bone can wave the ultrasound wand over their own thigh themselves. No need for batteries, and no need for invasive removal surgery once the bone is healed.

"The electrical field relates to the natural signal generated by your body at the injury location. We can sustain that voltage, on demand and reversible," for however long is needed using ultrasound, says UConn biomedical engineer Thanh Nguyen. The piezoelectric polymer Nguyen and his colleagues use to build the scaffold is called poly(L-lactic acid), or PLLA. In addition to being non-toxic and piezoelectric, PLLA gradually dissolves in the body over time, disappearing as the new bone grows.

"The electric field created by the piezoelectric PLLA scaffold seems to attract bone cells to the site of the fracture and promote stem cells to evolve into bone cells. This technology can possibly be combined with other factors to facilitate regeneration of other tissues, like cartilage, muscles or nerves," says Ritopa Das, a graduate student in Nguyen group and the first author of the published paper.

Currently Nguyen and his colleagues are working to make the polymer more favorable to bone growth, so that it heals a large fracture more quickly. They are also trying to understand why electrical fields encourage bone growth at all. Bone itself is somewhat piezoelectric, generating a surface charge when the bone is stressed by everyday life activities. That surface charge encourages more bone to grow. But scientists don't know whether it's because it helps cells stick to the surface of the bone, or whether it makes the cells themselves more active.

"Once we understand the mechanism, we can devise a better way to improve the material and the whole approach of tissue stimulation," Nguyen says.

Microplastic pollution in marine environments is concentrated most highly in coastal habitats, especially fjords and estuaries, according to a new review article published in the journal Marine Pollution Bulletin. Deep sea environments generally have much lower microplastic concentrations, although there are hotspots where elevated concentrations of microplastic occur.

Each year humans produce 360 million tonnes of plastic, and according to one study, around 8 million tonnes of it enters the ocean. Until recently the fate of microplastics (particles less than 5 mm in size) in the ocean has been unclear, but recent research has found that microscopic particles often settle in marine sediments, following the pattern of other pollutants.

The new review article - written by marine geologist Peter Harris, managing director of GRID-Arendal - includes information from more than 80 research papers that each reported measurements of microplastic found in sediments in one or more marine environments. Combining the results of all 80 papers shows that the overall pattern of microplastic pollution mirrors the pathways of natural sediment accumulation in which most material is deposited close to its input source, at the mouths of rivers and generally close to the coastline. Some environments, like fjords, lagoons, and estuaries, are naturally more efficient at trapping sediment and microplastic particles. Others, including highly energetic beaches and wave- and tide-dominated river deltas and estuaries, show less microplastic accumulation; they leak a significant fraction of especially fine sediments and microplastic particles to deep-water, offshore environments.

Microplastic pollution was found in fjords at a median concentration of around 7,000 particles per kilogram, and in some cases as high as 200,000 particles per kilogram of sediment. Concentrations were found to be lower in other marine environments: around 300 particles per kilogram in estuarine environments, 200 in beaches, and 80 in deep sea environments.

The article identified critical gaps that should be addressed by further research. More measurements of microplastic accumulation rates are needed from different environments in order to model the actual fate of microplastic pollution in the marine environment. Around 80% of published studies are from beach environments, as beaches are easily accessible for collecting samples, but more study is needed of other environments such as estuaries, lagoons, and fjords. Also, more measurements of the mass of microplastics (i.e. grams of plastic per kilogram of sediment) are needed. Only three out of the 80 studies surveyed included data on the mass of microplastics, while the vast majority of studies reported on the number of particles per kilogram of sediment. In order to understand how microplastic is dispersed in the ocean, we need quantitative data on the rate of the mass of plastic accumulating (g m-2 yr-1) from many different environments.

The findings of this work will be included in a new marine litter vital graphics publication that is being prepared by GRID-Arendal in collaboration with the UN Environment Programme.

New York, NY--June 30, 2020--SARS-CoV-2, the coronavirus causing the global COVID-19 pandemic, uses a protein called polymerase to replicate its genome inside infected human cells. Terminating the polymerase reaction will stop the growth of the coronavirus, leading to its eradication by the human host's immune system.

Researchers at Columbia Engineering and the University of Wisconsin-Madison have identified a library of molecules that shut down the SARS-CoV-2 polymerase reaction, a key step that establishes the potential of these molecules as lead compounds to be further modified for the development of COVID-19 therapeutics. Five of these molecules are already FDA-approved for use in the treatment of other viral infections including HIV/AIDS, cytomegalovirus, and hepatitis B. The new study was published on June 18, 2020, in Antiviral Research.

The Columbia team initially reasoned that the active triphosphate of the hepatitis C drug sofosbuvir and its derivative could act as a potential inhibitor of the SARS-CoV-2 polymerase based on the analysis of their molecular properties and the replication requirements of both the hepatitis C virus and coronaviruses. Led by Jingyue Ju, Samuel Ruben-Peter G. Viele Professor of Engineering, professor of chemical engineering and pharmacology, and director of the Center for Genome Technology & Biomolecular Engineering at Columbia University, they then collaborated with Robert N. Kirchdoerfer, assistant professor of biochemistry and an expert in the study of coronavirus polymerases at University of Wisconsin-Madison's Institute for Molecular Virology and the department of biochemistry.

In an earlier set of experiments testing the properties of the polymerase of the coronavirus that causes SARS, the researchers found that the triphosphate of sofosbuvir was able to terminate the virus polymerase reaction. They then demonstrated that sofosbuvir and four other nucleotide analogues (the active triphosphate forms of the HIV inhibitors Alovudine, Zidovudine, Tenofovir alafenamide, and Emtricitabine) also inhibited the SARS-CoV-2 polymerase with different levels of efficiency.

Using the molecular insight gained in these investigations, the team devised a strategy to select 11 nucleotide analogue molecules with a variety of structural and chemical features as potential inhibitors of the polymerases of SARS-CoV and SARS-CoV-2. While all 11 molecules tested displayed incorporation, six exhibited immediate termination of the polymerase reaction, two showed delayed termination, and three did not terminate the polymerase reaction.

Prodrug medications of five of these nucleotide analogues (Cidofovir, Abacavir, Valganciclovir/Ganciclovir, Stavudine, and Entecavir) that terminate the SARS-CoV-2 polymerase reaction are FDA-approved for the treatment of other viral infections and their safety profiles are well established. Once the potency of the drugs to inhibit viral replication in cell culture is demonstrated in future investigations, then the candidate molecules and their modified forms may be evaluated for the development of potential COVID-19 therapies.

"In our efforts to help tackle this global emergency, we are very hopeful that the structural and chemical features of the molecules we identified, in correlation with their inhibitory activity to the SARS-CoV-2 polymerase, can be used as a guide to design and synthesize new compounds for the development of COVID-19 therapeutics," says Ju. "We are extremely grateful for the generous research support that enabled us to make rapid progress on this project. I am also grateful for the outstanding contributions made by each member of our collaborative research consortium."