Tech

Among the many avenues that viruses can use to infect humans, drinking water may pose only a tiny risk for spreading certain viruses like the novel coronavirus. However, in cases where there is unauthorized wastewater disposal or other events of inadvertent mixing of wastewater with water sources, the possibility of transmission through drinking water remains unknown.

Using a surrogate of the coronavirus that only infects bacteria, researchers at Texas A&M University have now presented strong evidence that existing water purification plants can easily reduce vast quantities of the virus thereby protecting our household water from such contagions. In particular, the researchers showed that the water purification step called coagulation could alone get rid of 99.999% of the virus, markedly decontaminating water for consumption.

"We did not want to wait till drinking water became a potential cause for concern for coronavirus transmission," said Shankar Chellam, professor in the Zachry Department of Civil and Environmental Engineering. "This study shows that decontamination technologies that are already in place in water treatment facilities can remove or inactivate the coronavirus and other viruses that are structurally similar."

Details of their study were published in the American Chemical Society journal Environmental Science and Technology.

Viruses can be categorized between two structural types: those that have an outer fortress, called an envelope, and those that do not. This envelope, consisting of a lipid bilayer and attached proteins, has multiple functions, including aiding the virus in entering host cells. Several infamous viruses have a protective envelope, including coronaviruses and the Ebola virus.

Studies have found both enveloped and nonenveloped viruses in wastewater. However, most research has solely focused on the survival of nonenveloped viruses after wastewater and water treatment.

"It is well known that wastewater mixes with drinking water supplies. In fact, in many countries, including the United States, wastewater is purified and used as drinking water," Chellam said. "If enveloped viruses persist in wastewater, there could be a minuscule chance that these viruses make it into our drinking water supplies. We just don't know for sure."

At treatment facilities, raw water generally undergoes a three-step purification process: coagulation, followed by filtration and disinfection. In the coagulation step, certain metallic salts are added to initiate particles suspended in water to join together into millimeter-sized clumps. These clumps then settle down as sediment and are easily separated from the water. Chellam and his collaborators tested to see if enveloped viruses also assembled into bundles during coagulation.

For their experiments, they added a surrogate of the coronavirus that specifically infects bacteria to clean water. Next, they separately tested the action of a coagulant commonly used in water treatment plants. After coagulation, they studied small samples of the virus-infused water under an electron microscope and found that the virus strain assembled on the coagulants, forming clusters. They then checked the presence of infectious viruses in the water after removing the clumps and they found there was a 100,000 reduction.

"The U.S. Environmental Protection Agency mandates 99.99% of the viruses must be removed or inactivated from drinking water, and we found that even without filtration and chlorination, we were getting rid of 99.999% of the viruses," Chellam said.

The researchers noted that although they used the coronavirus surrogate for their study, the results are readily generalizable to other viruses that have similar surface characteristics, notably a lipid bilayer envelope and similar spike proteins. However, Chellam said that in the real world, wastewater contains a whole slew of viruses, unlike their experiments that included just a single strain of virus. In their next set of experiments, they plan to investigate if coagulation is still as effective at decontamination in these scenarios.

"Our work suggests that surface water treatment plants might be already well equipped to meet virus regulations for drinking water," Chellam said. "And coagulation is just the first step in the water purification pipeline. This is very encouraging since additional purification steps will only attenuate enveloped viruses further, alleviating associated health risks even more."

TAMPA, Fla. -- The prognosis of ovarian cancer is poor, with an estimated five-year survival of only 40% for advanced disease, the stage at which most ovarian carcinomas are diagnosed. These poor outcomes are partly due to the lack of effective therapies for advanced disease and recurrence. Immunotherapies hold promise for many types of cancer; however, studies have shown that patients with ovarian cancer do not have strong responses to existing drugs. In a new article published in Nature, Moffitt Cancer Center researchers demonstrate why some ovarian cancer patients evolve better than others and suggest possible approaches to improve patient outcomes.

Immunotherapeutic drugs activate T cells, a type of immune cell, to put up a defense against tumor cells. Immunotherapies are approved to treat several different types of cancer and have greatly changed the standard of care and improved patient outcomes. However, in ovarian cancer, clinical studies using immunotherapies aimed at stimulating T cells resulted in modest response rates. Studies have suggested that cancer patients who have a higher presence of other immune cells, such as plasma and memory B cells, could respond better to immunotherapies, but how these cell types promote better outcomes is unclear. Moffitt researchers wanted to confirm whether antibodies produced by these cells are associated with better outcomes and assess how these cells contribute to the spontaneous anti-tumor immune response against ovarian cancer.

The researchers analyzed a panel of 534 samples from ovarian cancer patients and found that patients who had a higher infiltration of B cells or B cell-derived plasma cells had better outcomes. B cells are a type of immune cell that produce antibodies and express one of five types of B cell receptors on their surface: IgM, IgD, IgG, IgE or IgA. These isotypes regulate different B cell signaling pathways and control B cell processes.

The surprise came when, upon further analysis of the samples, the Moffitt team discovered that the antibodies produced by B and plasma cells were predominantly of the IgA subtype, followed by IgG.

"We found that the presence of IgA regulated downstream signaling pathways of the ovarian cancer cells. Specifically, IgA resulted in inhibition of the RAS signaling pathway, which is known to contribute to ovarian cancer development," said Jose Conejo-Garcia, M.D., Ph.D., chair of Moffitt's Immunology Department.

This inhibition of RAS sensitized the tumor cells to T cell mediated cell killing, produced by both novel CAR T cells and tumor-infiltrating lymphocytes. The team also assessed that IgA and IgG secreted by the B cells recognized specific ovarian tumor cell surface markers and stimulated other immune cells called myeloid cells to target ovarian cancer cells for destruction.

These data provide new insights into how components of the immune system regulate ovarian cancer progression and offer new opportunities to develop improved targeted agents. This includes a repertoire of tumor-derived antibodies that can be effectively used as novel immunotherapeutic agents. In addition, the study provides a mechanistic rationale for integrated antibody responses in the development of novel immunotherapies, which until now have been based on T cell-centric approaches.

"The findings indicate that immunotherapies that boost both coordinated B and T cell responses against ovarian cancer, an immunogenic disease currently resistant to checkpoint inhibitors, are likely to show superior therapeutic benefit," said Subir Biswas, Ph.D., first author and postdoctoral fellow in the Conejo-Garcia lab.

Antimicrobial packaging is being developed to extend the shelf life and safety of foods and beverages. However, there is concern about the transfer of potentially harmful materials, such as silver nanoparticles, from these types of containers to consumables. Now, researchers reporting in ACS Applied Materials & Interfaces illustrate that silver embedded in an antimicrobial plastic can leave the material and form nanoparticles in foods and beverages, particularly in sweet and sugary ones.

Some polymers containing nanoparticles or nanocomposites can slow the growth of microorganisms responsible for food and beverage spoilage and foodborne illness. Although these polymers are not currently approved for use in packaging in the U.S., researchers are investigating various types of nanoparticle-embedded polymers that could be incorporated into containers in the future. Prior studies have shown that some of these polymers can leach nanoparticles, dissolved compounds and ions into water-based food simulants, but so far, little is known about how such packaging might interact with real foods and beverages. Some sugar compounds, which are typical food ingredients, can effectively convert silver ions into potentially harmful nanoparticles, and could then be ingested by humans. So, Timothy Duncan and colleagues wanted to see how the complex ingredients in sugary foods and beverages influenced the formation of these nanoparticles, both when directly exposed to dissolved silver and when they are stored inside silver-laced packaging.

To test if dissolved silver aggregates in complex edible mixtures, the researchers spiked silver into liquid foods and beverages, including naturally and artificially sweetened solutions, soda, milk, juices, yogurt and a starch-based slurry. The mixtures were incubated at 104 F for 10 or more days, simulating long-term storage in a packaging material. Nanostructures were detected at two silver concentrations, one at the scale expected from polymer-contact leaching, and the other at an unrealistically high concentration, allowing the team to monitor nanoparticle formation by eye. Sugary liquids with starches, citrates and fats had the most nanoparticles, while acidic liquids initially formed silver aggregates that later dissolved. In another experiment, the researchers stored water and two sugary liquids in small packets of silver-laced polyethylene polymer at 104 F for 15 days. There was an initial release of dissolved silver from the polymer surface, but only the sugary solutions sustained further leaching and the creation of nanoparticles. The researchers concluded that silver nanoparticle dietary exposure is possible from sweetened foods and beverages packaged in antimicrobial materials under the conditions typical of long-term storage.

Researchers have identified a pattern of deletions in the spike (S) glycoprotein of SARS-CoV-2 that can prevent antibody binding. Virus lineages featuring this mechanism are currently being transmitted between individuals globally, they say. Their results - reported after analyzing nearly 150,000 S gene sequences collected from many parts of the world - exhibit a form of virus "escape" that resulted from a common, strong selective pressure; for example, the authors identified at least nine instances where deletion variants arose in patients whose COVID-19 infections were persistent. So far, the strongest indicator of protection against SARS-CoV-2 appears to be humoral immunity, such as by antibodies, to the S protein. Recently approved vaccines deliver the S protein, training the body to recognize and attack it. Whether SARS-CoV-2's S protein will evolve the ability to evade the immune system through mechanisms like deletions, which virus proofreading cannot correct, remains unknown. Using samples from a cancer patient infected with COVID-19 who died 74 days after COVID-19 diagnosis, Kevin McCarthy and colleagues cloned S genes and identified variants with deletions. This prompted them to investigate patient metadata sequences deposited in a database, called GISAID, containing whole-genome sequences of SARS-CoV-2. They identified more patients with deletions in the S protein. Searching nearly 150,000 sequences in the full GISAID database, they found 1,108 additional instances of viruses that exhibited deletions in S. By examining the atomic structure of the S protein, McCarthy and colleagues mapped these deletions to defined antigenic sites. This led them to develop the hypothesis that these deletions would produce viruses that no longer bind a published strongly neutralizing antibody. Using a panel of deletion mutations, they confirmed this hypothesis. The deletions they uncovered have repeatedly arisen in genetically distinct viruses, at various times, in multiple countries, the authors say. During evaluation of this manuscript," they note, "multiple lineages with altered antigenicity and perhaps increased transmissibility have emerged and spread." They conclude: "These real-world outcomes demonstrate the predictive potential of this and like approaches and show the need to monitor viral evolution carefully and continually."

URBANA, Ill. - For decades, kibble has been our go-to diet for dogs. But the dog food marketplace has exploded in recent years, with grain-free, fresh, and now human-grade offerings crowding the shelves. All commercial dog foods must meet standards for complete and balanced nutrition, so how do consumers know what to choose?

A new University of Illinois comparison study shows diets made with human-grade ingredients are not only highly palatable, they're extremely digestible. And that means less poop to scoop. Up to 66% less.

"Based on past research we've conducted I'm not surprised with the results when feeding human-grade compared to an extruded dry diet," says Kelly Swanson, the Kraft Heinz Company Endowed Professor in Human Nutrition in the Department of Animal Sciences and the Division of Nutritional Sciences at Illinois, and co-author on the Journal of Animal Science study. "However, I did not expect to see how well the human-grade fresh food performed, even compared to a fresh commercial processed brand."

Swanson and his team fed beagles four commercially available diets: a standard extruded diet (kibble); a fresh, refrigerated diet; and two fresh diets made using only USDA-certified human-grade ingredients. These fresh diets include minimally processed ingredients such as beef, chicken, rice, carrots, broccoli, and others in small chunks or a sort of casserole. The dogs consumed each diet for four weeks.

The researchers found that dogs fed the extruded diet had to eat more to maintain their body weight, and produced 1.5 to 2.9 times as much poop as any of the fresh diets.

"This is consistent with a 2019 National Institute of Health study in humans that found people eating a fresh whole food diet consumed on average 500 less calories per day, and reported being more satisfied, than people eating a more processed diet," Swanson says.

The researchers also found that the fresh diets uniquely influenced the gut microbial community.

"Because a healthy gut means a healthy mutt, fecal microbial and metabolite profiles are important readouts of diet assessment," Swanson says. "As we have shown in previous studies, the fecal microbial communities of healthy dogs fed fresh diets were different than those fed kibble. These unique microbial profiles were likely due to differences in diet processing, ingredient source, and the concentration and type of dietary fibers, proteins, and fats that are known to influence what is digested by the dog and what reaches the colon for fermentation."

Commercially available, fresh prepared whole-food diets have been around for a decade and despite anecdotal reports of health benefits, some nutrition experts were concerned about a lack of scientific evidence to support the feeding of these diets. Swanson published an earlier study in roosters to show the same human-grade fresh diets were up to 40% more digestible than kibble, and his new study in dogs strengthens those findings.

Piezoelectric materials hold great promise as sensors and as energy harvesters but are normally much less effective at high temperatures, limiting their use in environments such as engines or space exploration. However, a new piezoelectric device developed by a team of researchers from Penn State and QorTek remains highly effective at elevated temperatures.

Clive Randall, director of Penn State's Materials Research Institute (MRI), developed the material and device in partnership with researchers from QorTek, a State College, Pennsylvania-based company specializing in smart material devices and high-density power electronics.

"NASA's need was how to power electronics in remote locations where batteries are difficult to access for changing," Randall said. "They also wanted self-powering sensors that monitor systems such as engine stabilities and have these devices work during rocket launches and other high-temperature situations where current piezoelectrics fail due to the heat."

Piezoelectric materials generate an electric charge when rapidly compressed by a mechanical force during vibrations or motion, such as from machinery or an engine. This can serve as a sensor to measure changes in pressure, temperature, strain or acceleration. Potentially, piezoelectrics could power a range of devices from personal electronics like wristband devices to bridge stability sensors.

The team integrated the material into a version of a piezoelectric energy harvester technology called a bimorph that enables the device to act either as a sensor, an energy harvester or an actuator. A bimorph has two piezoelectric layers shaped and assembled to maximize efficient energy harvesting. Sensors and energy harvesters, while bending the bimorph structure, generate an electrical signal for measurement or act as a power source.

Unfortunately, these functions work less-effectively in high-temperature environments. Current state-of-the-art piezoelectric energy harvesters are normally limited to a maximum effective operating temperature range of 176 degrees Fahrenheit (80 degrees Celsius) to 248 degrees Fahrenheit (120 degrees C).

"A fundamental problem with piezoelectric materials is their performance starts to drop pretty significantly at temperatures above 120 C, to the point where above 200 C (392 F) their performance is negligible," Gareth Knowles, chief technical officer of QorTek, said. "Our research demonstrates a possible solution for that for NASA."

The new piezoelectric material composition developed by the researchers showed a near-constant efficient performance at temperatures up to 482 F (250 C). In addition, while there was a gradual drop-off in performance above 482 F (250°C), the material remained effective as an energy harvester or sensor at temperatures to well-above 572 F the researchers reported in the Journal of Applied Physics.

"The compositions performing just as well at these high temperatures as they do at room temperature is a first, as no one has ever managed piezoelectric materials that effectively operate at such high temperatures," Knowles said.

Another benefit of the material was an unexpectedly high level of electricity production. While at present, piezoelectric energy harvesters are not at the level of more efficient power producers such as solar cells, the new material's performance was strong enough to open possibilities for other applications, according to Randall.

"The energy production part of this was very impressive, the material shows record performance efficiencies as a piezoelectric energy harvester," Randall said. "This would potentially enable a continuous, battery-free power supply in dark or concealed environments such as inside an automotive system or even the human body."

Both Randall and Knowles noted that the partnership between Penn State and QorTek, which goes back over 20 years, enabled development of the new, improved piezoelectric material by complementing each other's resources.

"In general, a big benefit of a partnership like this is you can tap into the large knowledge reservoir in the field that MRI and Penn State has and that small companies like ours sometimes do not," Knowles said. "Another benefit is often universities have physical resources such as equipment that again, you won't ordinarily find inside a small company."

Randall noted that since QorTek has many employees who are Penn State alumni, there is a familiarity with both the research subject and the people involved.

"One of my post-doctoral researchers and first author on the paper, Wei-Ting Chen, was hired by QorTek so there was a transfer of expertise in that case," Randall said. "Also, the skillsets offered by QorTek such as mechanical engineering, device design and measurement expertise pushed development at a much faster rate than would be possible given the budget we were given. So the partnership enabled a really fruitful amplification of the project."

DURHAM, N.C. -- Harsher immigration law enforcement by U.S. Immigration and Customs Enforcement leads to decreased use of prenatal care for immigrant mothers and declines in birth weight, according to new Duke University research.

In the study, published in PLOS ONE, researchers examine the effects of the federal 287(g) immigration program after it was introduced in North Carolina in 2006. Under 287(g) programs, which are still in effect, local law officers are deputized to act as Immigration and Customs Enforcement (ICE) agents, with authority to question individuals about immigration status, detain them, and if necessary, begin deportation proceedings.

According to the study findings, the 2006 policy change reduced birth weight by an average of 58.54 grams. It also resulted in more births of babies who were small for their gestational age. Those births rose by 2.29 percentage points.

In addition, immigrant parents used less prenatal care, meaning they either did not see a health care provider in the first trimester or missed at least half of their recommended prenatal visits.

"There are economic costs to adverse birth outcomes, both for children involved and to society," said Marcos Rangel, co-author of the study and professor of public policy at Duke University's Center for Child and Family Policy. "The recent uptick in ICE activities under the Trump administration may have long-lasting, harmful effects on U.S.-born citizens."

The study is believed to be the first to examine how the 287(g) program affects infant health. Using administrative data from 2004 to 2006, researchers examined birth and maternal health outcomes for immigrant mothers residing in Mecklenburg County before and after the 287(g) program was implemented. They then compared the Mecklenburg data with similar statistics in counties that did not adopt the programs. Mecklenburg is home to the state's largest city, Charlotte.

The researchers did not identify why immigrant women used less prenatal care. However, the authors suggest that fear may be one motivation.

"If going to the doctor means you might run into ICE, maybe you don't go," said Christina Gibson-Davis, professor of public policy and sociology. "It wasn't the intention of the policy, but pregnant women not getting adequate prenatal care is worrying."

To understand the magnitude of the effects, the researchers compared their findings to the benefits of participating in programs like the Supplemental Nutrition Program for Women, Infants, and Children (WIC) and the Supplemental Nutrition Assistance Program (SNAP).

"The adverse effects of the 287(g) program essentially counteracted the beneficial effects of participating in SNAP or WIC," said Romina Tome, an economics researcher at American Institutes for Research and a recent Ph.D. graduate of Duke University's Sanford School of Public Policy. "Exposure to policies during pregnancy can either be harmful or hurtful. These ICE policies appear to be harmful."

As a native animal, kangaroos aren't typically considered a threat to Australian vegetation.

While seen as a pest on farmland - for example, when competing with livestock for resources - they usually aren't widely seen as a pest in conservation areas.

But a new collaborative study led by UNSW Sydney found that conservation reserves are showing signs of kangaroo overgrazing - that is, intensive grazing that negatively impacts the health and biodiversity of the land.

Surprisingly, the kangaroos' grazing impacts appeared to be more damaging to the land than rabbits, an introduced species.

"The kangaroos had severe impacts on soils and vegetation that were symptomatic of overgrazing," says Professor Michael Letnic, senior author of the paper and professor in conservation biology and ecosystem restoration at UNSW Science.

"Not only did the areas grazed by overabundant kangaroos have fewer species of plants, but the soils were depleted in nutrients and were compacted - which means that less water can be absorbed by the soil when it rains."

The findings, published late last year in Global Ecology and Conservation, are based on fieldwork conducted in conservation areas during the drought in 2018. The researchers made observations across four conservation reserves in semi-arid parts of the country.

While kangaroos and rabbits can roam freely in these areas, each reserve has several small 'exclosures' - fenced sections designed to keep unwanted animals out - to help native vegetation regenerate. These areas excluded either rabbits, kangaroos, or both.

The team compared the health of the soil and vegetation inside the exclosures with the areas outside. They looked for signs of land degradation specific to each species and monitored animal populations in the area.

Kangaroos were the most populous herbivore across all reserves.

"We tend to think of kangaroo grazing as a natural process because they're a native species, but there are now too many kangaroos in conservation reserves," says Prof. Letnic. "Their grazing can be detrimental for biodiversity conservation.

"We need to start thinking about developing strategies to restore the balance and reduce the adverse impacts of overgrazing - particularly during times of drought."

Dr Graeme Finlayson, SA Arid Rangeland ecologist for Bush Heritage, says overgrazing had dire implications for other native species who rely on vegetation cover and associated food resources to survive. Bush Heritage owns and manages Boolcoomatta Reserve, one of the conservation sites included in this study.

"One of the key species that is likely to be impacted by overgrazing is the critically endangered Plains Wanderer (Pedionomus torquatus), of which there are less than 1000 left in the wild," he says. "Despite sighting three birds at Boolcoomatta in May 2019, monitoring on the reserve has failed to detect any birds since then.

"Overgrazing and then a two-year drought which have greatly reduced cover and food resources are likely to be key drivers behind this."

A dry and delicate ecosystem

Ecosystems are fragile and can be thrown off-balance by an overabundance of one species.

For example, kangaroo overgrazing leads to a lower plant diversity - and fewer plants means less food and shelter for other animals.

Dr Charlotte Mills, lead author of the study and visiting fellow at UNSW Science, hopes that this study paves the way for future research into how threatened species might be affected by kangaroo overgrazing.

"There isn't a lot of research about how kangaroos differentially affect different parts of the ecosystem," she says. "A lot of past research has focused on rabbits."

The team found that rabbits still had negative impacts on the land - for example, there were more woody plants in exclosures that rabbits couldn't get to - but not to the same degree as kangaroos.

"Rabbits and other introduced herbivores like goats are often considered the main contributor to overgrazing in Australia," says Dr Mills.

"But we found kangaroos had a greater impact on the land - and on the grass in particular."

Human intervention is a key contributing factor to the growth of kangaroo populations.

"Humans have been culling dingoes - kangaroos natural predators," says Prof. Letnic.

"We've been making it easier for kangaroos to thrive."

Rethinking conservation practices

Conservation reserves help protect native vegetation from threats like grazing from livestock or introduced species like rabbits or goats.

The findings suggest native species might need to be kept in check, too.

"If we aren't managing threats that have been exacerbated by human activities - such as overabundant kangaroo populations - then we're not using conservation areas in the best way that we can," says Dr Mills.

Prof. Letnic says that while kangaroo populations on farms have been managed for 100 years, they have generally been unmanaged on conservation reserves.

"This research changes thinking by suggesting it's time to ask some questions," he says. "We need to ask whether there are too many kangaroos and if they're having unacceptable impacts on our conservation reserves."

Dr Finlayson says it's a difficult balance to get right, but a humane and science-led approach is best for the entire ecosystem.

"Reducing total grazing pressure clearly has great conservation benefit but can be a challenging issue when this requires the management of native species, such as kangaroos," he says.

"We need to make sure we have a landscape-wide strategy, working across government, conservation and agriculture, to ensure we tackle this problem together, and in the most humane way possible."

Mathematicians from RUDN University suggested and tested a new method to assess the productivity of fifth-generation (5G) base stations. The new technology would help get rid of mobile access stations and even out traffic fluctuations. The results of the study were published in the IEEE Conference Publication.

Stations of the new 5G New Radio (NR) communication standard developed by the 3GPP consortium are expected to shortly be installed in large quantities all over the world. First of all, the stations will be deployed in places with high traffic use and at public event locations (e.g. shopping malls, city squares, or stadiums). In these conditions, the number of active communication sessions continually changes, and such traffic fluctuations can dramatically reduce network capacity. Traditionally, this issue has been solved with mobile stations (drones or cars), but they cannot be used in a closed space such as a shopping mall. Moreover, they are unable to even out traffic fluctuations on the sub-minute scale (i.e. within periods less than 1 minute). A team of mathematicians from RUDN University suggested a 5G network deployment scheme that provides for the mitigation of traffic fluctuations on the sub-minute level and can be rolled out in closed spaces.

"The 5G NR technology promises exceptionally high speed on the final mile--a channel that connects a user's device with a provider's access point. The connection is expected to be extremely fast within the millimeter waves range. The new technology is supposed to satisfy the growing needs of users. Our approach could help deploy 5G in busy public places and effectively even out traffic fluctuations," explained Anastasia Daraseliya, a postgraduate student at the Institute for Applied Mathematics and Telecommunications, RUDN University.

The idea suggested by RUDN mathematicians lies in using two technologies at once: NR and the so-called WiGig--60-gigahertz Wi-Fi with a data transmission rate up to 7 Gb/sec. By aggregating a licensed and a non-licensed band spectrum, one could shed some of the load to the non-licensed band and thus increase the transmission speed. Both technologies operate in the millimeter waves range and therefore are adjusted to each other by default. The team also assumed that both technologies would be widely supported by modern-day and future devices.

The team studied the joint user traffic query serving by base stations using a combination of NR and WiGig and analyzed the future applicability of this system. To do so, they used several methods of stochastic geometry, Markovian chain theory, and queueing theory. The team described the methodology of interaction between the two standards in one base station and concluded that the new approach would support continuous 5G communication in busy public places without losing transmission capacity even in cases of sub-minute traffic drops

"Having determined the density of base station and taking into account the density of user devices, we suggested a performance assessment structure for joint use of NR and WiGig. Although in the model the two systems are located close to each other, they do not exchange data. Therefore, such a structure can be deployed in any necessary configuration depending on conditions and requirements," added Anastasia Daraseliya from RUDN Unviersity.

ITHACA, N.Y. -Wind energy scientists at Cornell University have released a new global wind atlas - a digital compendium filled with documented extreme wind speeds for all parts of the world - to help engineers select the turbines in any given region and accelerate the development of sustainable energy.

This wind atlas is the first publicly available, uniform and geospatially explicit (datasets tied to locations) description of extreme wind speeds, according to the research, "A Global Assessment of Extreme Wind Speeds For Wind Energy Applications," published in Nature Energy.

"Cost-efficient expansion of the wind-energy industry is enabled by access to this newly released digital atlas of the extreme wind conditions under which wind turbines will operate at locations around the world," said Sara C. Pryor, professor in the Department of Earth and Atmospheric Sciences, who authored the paper with Rebecca J. Barthelmie, professor in the Sibley School of Mechanical and Aerospace Engineering. Both are faculty fellows at the Cornell Atkinson Center for Sustainability.

"This kind of information will ensure the correct selection of wind turbines for specific deployment," Pryor said, "and help ensure cost-efficient and dependable electricity generation from those turbines."

Knowing extreme wind speeds is key to turbine design for cost effectiveness, proper turbine selection and structural integrity on any given site, said the researchers. Before, in many locations, extreme wind-load estimates on projects were uncertain due to limited on-site measurements.

By the end of 2019, total global wind turbine installed capacity was more than 651 gigawatts (GW), according to the paper, thanks to 60 GW of recently built capacity - of which nearly 90% was placed onshore. "Thus, wind is now generating over 1,700 terawatt hours of electricity per year or about 7.5% of the global electricity supply," Pryor said.

Barthelmie and Pryor report that the United States carries 17% of the world's current wind energy installed capacity, while Europe (31%) and China (36%) carry more.

There are now wind turbines generating carbon-free electricity in more than 90 countries, Pryor said.

Development of research product was motivated by a need from the wind-energy industry, Barthelmie said. Quantifying extreme winds may also be useful in civil engineering applications and in structural reliability analyses for tall buildings and transportation systems - including long-span bridges - as well as for electricity generation and distribution.

"Further cost-efficient expansion of the wind-energy industry will be enabled by access to this newly released digital atlas," Pryor said.

Despite worldwide use of lithium batteries, the exact dynamics of their operation has remained elusive. X-rays have proven to be a powerful tool for peering inside of these batteries to see the changes that occur in real time.

Using the ultrabright X-rays of the Advanced Photon Source (APS), a U.S. Department of Energy (DOE) Office of Science User Facility at the DOE’s Argonne National Laboratory, a research team recently observed the internal evolution of the materials inside solid-state lithium batteries as they were charged and discharged. This detailed 3D information may help improve the reliability and performance of the batteries, which use solid materials to replace the flammable liquid electrolytes in existing lithium-ion batteries.

“There is substantial commercial and scientific interest in this area, and information from this study should help advance this technology toward broad commercial applications.” — Matthew McDowell, Georgia Institute of Technology

Using a small (roughly two millimeters wide) cylindrical battery, researchers at APS beamline 2-BM were able to capture 3D images of structural changes during the battery charge and discharge cycles as they happened.

“The main features of this beamline that made this research possible are the high sensitivity and very fast speed,” said Francesco De Carlo, group leader with Argonne’s X-ray Science division and a co-author on the paper. “The sensitivity helped the team differentiate between phases inside the battery with similar densities, and the speed allowed them to capture the changes inside the battery while the process was evolving.”

These clear images revealed how the dynamic changes of electrode materials at lithium/solid-electrolyte interfaces determine the behavior of solid-state batteries. The researchers found that battery operation caused tiny voids — resolved up to 1-2 microns in size, about 50 times smaller than the width of a human hair — to form at the interface, which created a loss of contact that was the primary cause of failure in the cells.

“This work provides fundamental understanding of what is happening inside the battery, and that information should be important for guiding engineering efforts that will push these batteries closer to commercial reality in the next several years,” said Matthew McDowell, an author on the paper and an assistant professor in the George W. Woodruff School of Mechanical Engineering and the School of Materials Science and Engineering at the Georgia Institute of Technology. “We were able to understand exactly how and where voids form at the interface, and then relate that to battery performance.”

The research was reported January 28 in the journal Nature Materials.

The lithium-ion batteries now in widespread use for everything from mobile electronics to electric vehicles rely on a liquid electrolyte to carry ions back and forth between electrodes within the battery during charge and discharge cycles. The liquid uniformly coats the electrodes, allowing free movement of the ions.

Rapidly-evolving solid state battery technology instead uses a solid electrolyte, which should help boost energy density and improve the safety of future batteries. But removal of lithium from electrodes can create voids at interfaces that cause reliability issues that limit how long the batteries can operate.

“To counter this, you could imagine creating structured interfaces through different deposition processes to try to maintain contact through the cycling process,” McDowell said. “Careful control and engineering of these interface structures will be very important for future solid-state battery development, and what we learned here could help us design interfaces.”

The Georgia Tech research team, led by first author and graduate student Jack Lewis, built special test cells which were designed to be studied at beamline 2-BM of the APS. Four members of the team studied the changes in battery structure during a five-day period of intensive experiments using X-ray computed tomography.

“The instrument takes images from different directions, and you reconstruct them using computer algorithms to provide 3D images of the batteries over time,” McDowell said. “We did this imaging while we were charging and discharging the batteries to visualize how things were changing inside the batteries as they operated.”

Because lithium is so light, imaging it with X-rays can be challenging and required a special design of the test battery cells. The technology used at Argonne is similar to what is used for medical computed tomography (CT) scans. “Instead of imaging people, we were imaging batteries,” he said.

Because of limitations in the testing, the researchers were only able to observe the structure of the batteries through a single cycle. In future work, McDowell would like to see what happens over additional cycles, and whether the structure somehow adapts to the creation and filling of voids. The researchers believe the results would likely apply to other electrolyte formulations, and that the characterization technique could be used to obtain information about other battery processes.

De Carlo also noted that a possible next step might be nanotomography, which uses a more tightly focused X-ray beam and can deliver pictures of even smaller voids in the batteries, should they form during operation. This technique is also possible at the APS.

Battery packs for electric vehicles must withstand at least a thousand cycles during a projected 150,000-mile lifetime. While solid-state batteries with lithium metal electrodes can offer more energy for a given size battery, that advantage won’t overcome existing technology unless they can provide comparable lifetimes.

“We are very excited about the technological prospects for solid-state batteries,” McDowell said. “There is substantial commercial and scientific interest in this area, and information from this study should help advance this technology toward broad commercial applications.”

The speed of light has come to 3D printing. Northwestern University engineers have developed a new method that uses light to improve 3D printing speed and precision while also, in combination with a high-precision robot arm, providing the freedom to move, rotate or dilate each layer as the structure is being built.

Most conventional 3D printing processes rely on replicating a digital design model that is sliced into layers with the layers printed and assembled upwards like a cake. The Northwestern method introduces the ability to manipulate the original design layer by layer and pivot the printing direction without recreating the model. This "on-the-fly" feature enables the printing of more complicated structures and significantly improves manufacturing flexibility.

"The 3D printing process is no longer a way to merely make a replica of the designed model," said Cheng Sun, associate professor of mechanical engineering at Northwestern's McCormick School of Engineering. "Now we have a dynamic process that uses light to assemble all the layers but with a high degree of freedom to move each layer along the way."

Sun led the research, which lies at the intersection of two of his main areas of focus: nanofabrication and optics. The study was published today (Feb. 3) by the journal Advanced Materials.

In the paper, the researchers demonstrate several applications, including 3D printing a customized vascular stent and printing a soft pneumatic gripper made of two different materials, one hard and one soft. A double helix and a tiny Eiffel Tower are two other printed examples in the study.

The Northwestern process uses a robotic arm and a liquid photopolymer that is activated by light. Sophisticated 3D structures are pulled out from a bath of liquid resin by a high-precision robot with enhanced geometric complexity, efficiency and quality compared to the traditional printing process. The arm is used to change the printing direction dynamically.

"We are using light to do the manufacturing," Sun said. "Shining light on the liquid polymer causes it to crosslink, or polymerize, converting the liquid to a solid. This contributes to the speed and precision of our 3D printing process -- two major challenges that conventional 3D printing is facing."

The continuous printing process can print 4,000 layers in approximately two minutes.

"This is a very fast process, and there is no interruption between layers," Sun said. "We hope the manufacturing industry will find benefit in it. The general printing method is compatible with a wide range of materials."

Looking to the future, Sun said this printing process could be applied to other additive as well as traditional subtractive manufacturing processes, providing a bridge toward a truly hybrid process.

Hikers, soldiers and school children all know the burden of a heavy backpack. But now, researchers have developed a prototype that not only makes loads feel about 20% lighter, but also harvests energy from human movements to power small electronics. The new backpack, reported in ACS Nano, could be especially useful for athletes, explorers and disaster rescuers who work in remote areas without electricity, the researchers say.

Backpacks are widely used in everyday life for the hands-free carrying of loads. Over time, however, walking or running with a heavy sack can cause back and neck pain. Also, backpackers in wilderness areas (or even those in cities who don't have ready access to a charger) might wish for a bag that could harvest the mechanical energy of walking to power portable electronics or health-monitoring sensors. Previously, researchers have used triboelectric nanogenerators (TENG) -- small devices that convert mechanical energy into electricity ¬¬-- to make energy-harvesting backpacks, but those bags had relatively low power outputs and they didn't provide added benefits, such as load lightening or shock absorption. Zhong Lin Wang, Jia Cheng and colleagues wanted to design a prototype that overcame these limitations.

To save labor and absorb shock, the researchers incorporated into the backpack two elastomers that stretched and shrank, keeping the bag steady as the wearer walked. This resulted in about a 20% reduced force on the wearer. Meanwhile, movement between the frame of the backpack and its load during walking drove a TENG to convert mechanical energy into electricity, with 14% efficiency. The researchers showed that the bag could power LEDs, an electric watch and fluorescent tubes. Once some challenges, such as improving the energy conversion efficiency, are overcome, the backpack has promising potential as a power source for small-scale wearable and portable electronics, GPSs and health care sensors, the researchers say.

Previous studies have linked sleep deprivation and frailty with depression. A new study published in the Journal of the American Geriatrics Society that examined their combined effect suggests that short sleep intensifies the impacts of frailty on depressive symptoms.

Among 5,026 community-dwelling older adults in China, participants who were frail at the start of the study were more likely to later develop depressive symptoms. Also, those who experienced worsening frailty throughout the study tended to develop higher levels of depression. Short sleep exacerbated these effects.

The findings suggest that interventions that target sleep disturbances--such as exercise and mindfulness-based stress reduction--might help alleviate the negative effects of frailty on psychological well-being.

"We hope our research findings raise people's awareness of the combined effect of frailty and sleep on older adults' mental health, and provide implications for interventions to improve sleep quality for prefrail and frail older adults," said co-author Xinyi Zhao, PhD, of Peking University, in Beijing.

Investigators have published a global review of mammal strikes with aircraft, noting that events have been increasing by up to 68% annually. More mammals were struck during the landing phase of an aircraft's rotation than any other phase, according to the article published in Mammal Review.

By analyzing published information and mammal strike data from national aviation authorities in Australia, Canada, France, Germany, the United Kingdom, and the United States, researchers found that bats accounted for the greatest proportion of strikes in Australia; rabbits and dog-like carnivores in Canada, Germany, and the United Kingdom; and bats and deer in the United States. Average mammal strikes per year ranged from 1.2 to 38.7 across the countries analyzed, for every million aircraft movements.

Over 30 years, the estimated cost of damage resulting from reported mammal strikes exceeded $103 million in the United States alone.

"Mammals are incredibly diverse and those involved in strike events are no exception. As we identified 47 countries which have reported strikes with mammals, the species involved ranged from some of the world's smallest mammals, such as voles, all the way up to the mighty giraffe and included mammals of all sizes in between. As strike events can affect everything from passenger safety, airline economics and local conservation, understanding the species composition and ecology of the local fauna at an airfield is paramount for effective strike mitigation," said lead author Samantha Ball of University College Cork, in Ireland.