Tech

COLUMBIA, S.C. -- May 15, 2020 -- Scientists at the University of South Carolina and Columbia University have developed a faster way to design and make gas-filtering membranes that could cut greenhouse gas emissions and reduce pollution.

Their new method, published today in Science Advances, mixes machine learning with synthetic chemistry to design and develop new gas-separation membranes more quickly. Recent experiments applying this approach resulted in new materials that separate gases better than any other known filtering membranes.

The discovery could revolutionize the way new materials are designed and created, Brian Benicewicz, the University of South Carolina SmartState chemistry professor, said.

"It removes the guesswork and the old trial-and-error work, which is very ineffective," Benicewicz said. "You don't have to make hundreds of different materials and test them. Now you're letting the machine learn. It can narrow your search."

Plastic films or membranes are often used to filter gases. Benicewicz explained that these membranes suffer from a tradeoff between selectivity and permeability ? a material that lets one gas through is unlikely to stop a molecule of another gas. "We're talking about some really small molecules," Benicewicz said. "The size difference is almost imperceptible. If you want a lot of permeability, you're not going to get a lot of selectivity."

Benicewicz and his collaborators at Columbia University wanted to see if big data could design a more effective membrane.

The team at Columbia University created a machine learning algorithm that analyzed the chemical structure and effectiveness of existing membranes used for separating carbon dioxide from methane. Once the algorithm could accurately predict the effectiveness of a given membrane, they turned the question around: What chemical structure would make the ideal gas separation membrane?

Sanat K. Kumar, the Bykhovsky Professor of Chemical Engineering at Columbia, compared it to Netflix's method for recommending movies. By examining what a viewer has watched and liked before, Netflix determines features that the viewer enjoys and then finds videos to recommend. His algorithm analyzed the chemical structures of existing membranes and determined which structures would be more effective.

The computer produced a list of 100 hypothetical materials that might surpass current limits. Benicewicz, who leads a synthetic chemistry research group, identified two of the proposed structures that could plausibly be made. Laura Murdock, a UofSC PhD student in chemistry, made the prescribed polymers and cast them into thin films.

When the membranes were tested, their effectiveness was close to the computer's prediction and well above presumed limits.

"Their performance was very good ? much better than what had been previously made," Murdock said. "And it was pretty easy. It has the potential for commercial use."

Separating carbon dioxide and methane has an immediate application in the natural gas industry; CO2 must be removed from natural gas to prevent corrosion in pipelines. But Murdock said the method of using big data to remove the guesswork from the process leads to another question: "What other polymer materials can we apply machine learning to and create better materials for all kinds of applications?"

Benicewicz said machine learning could help scientists design new membranes for separating greenhouse gases from coal, which can help to reduce climate change.

"This work thus points to a new way of materials design," Kumar said. "Rather than test all the materials that exist for a particular application, you look for the part of a material that best serves the need that you have. When you combine the very best materials then you have a shot at designing a better material."

Light is emerging as the leading vehicle for information processing in computers and telecommunications as our need for energy efficiency and bandwidth increases.

Already the gold standard for intercontinental communication through fibre-optics, photons are replacing electrons as the main carriers of information throughout optical networks and into the very heart of computers themselves.

However, there remain substantial engineering barriers to complete this transformation. Industry-standard silicon circuits that support light are more than an order of magnitude larger than modern electronic transistors. One solution is to 'compress' light using metallic waveguides - however this would not only require a new manufacturing infrastructure, but also the way light interacts with metals on chips means that photonic information is easily lost.

Now scientists in Australia and Germany have developed a modular method to design nanoscale devices to help overcome these problems, combining the best of traditional chip design with photonic architecture in a hybrid structure. Their research is published today in Nature Communications.

"We have built a bridge between industry-standard silicon photonic systems and the metal-based waveguides that can be made 100 times smaller while retaining efficiency," said lead author Dr Alessandro Tuniz from the University of Sydney Nano Institute and School of Physics.

This hybrid approach allows the manipulation of light at the nanoscale, measured in billionths of a metre. The scientists have shown that they can achieve data manipulation at 100 times smaller than the wavelength of light carrying the information.

"This sort of efficiency and miniaturisation will be essential in transforming computer processing to be based on light. It will also be very useful in the development of quantum-optical information systems, a promising platform for future quantum computers," said Associate Professor Stefano Palomba, a co-author from the University of Sydney and Nanophotonics Leader at Sydney Nano.

"Eventually we expect photonic information will migrate to the CPU, the heart of any modern computer. Such a vision has already been mapped out by IBM."

On-chip nanometre-scale devices that use metals (known as "plasmonic" devices) allow for functionality that no conventional photonic device allows. Most notably, they efficiently compress light down to a few billionths of a metre and thus achieve hugely enhanced, interference-free, light-to-matter interactions.

"As well as revolutionising general processing, this is very useful for specialised scientific processes such as nano-spectroscopy, atomic-scale sensing and nanoscale detectors," said Dr Tuniz also from the Sydney Institute of Photonics and Optical Science.

However, their universal functionality was hampered by a reliance on ad hoc designs.

"We have shown that two separate designs can be joined together to enhance a run-of-the-mill chip that previously did nothing special," Dr Tuniz said.

This modular approach allows for rapid rotation of light polarisation in the chip and, because of that rotation, quickly permits nano-focusing down to about 100 times less than the wavelength.

Professor Martijn de Sterke is Director of the Institute of Photonics and Optical Science at the University of Sydney. He said: "The future of information processing is likely to involve photons using metals that allow us to compress light to the nanoscale and integrate these designs into conventional silicon photonics."

New Rochelle, NY, May 15, 2020--Data collected over a 15-week period showed that using virtual care to manage diabetes patients in the hospital does not have a negative impact on their glycemic outcomes. This study, aimed at reducing provider and patient exposure during the COVID-19 pandemic, has broader implications for implementing telehealth to diabetes care in remote locations and to limit the transmission of hospital-acquired infections. The study is published in Diabetes Technology & Therapeutics (DTT), a peer-reviewed journal from Mary Ann Liebert, Inc., publishers. Click here to read the full-text article free on the Diabetes Technology & Therapeutics (DTT) website.

The article entitled "Inpatient Transition to Virtual Care During COVID-19 Pandemic" describes the use of "virtual care" care for inpatient diabetes care to reduce exposure to the COVID-19 virus and to reduce the use of personal protective equipment. Morgan Jones, MD and coauthors from University of North Carolina (UNC), Chapel Hill and Tufts University, Boston, MA, present a model for virtual care in which all face-to-face patient contact was stopped on March 22, 2020. Telehealth included a telephone interview with patients (or a family member or their primary nurse) each morning and occasional telemedicine visits by an endocrinologist. The researchers concluded that glycemic control was similar with the transition to virtual care.

"The COVID-19 pandemic has forced all of us to find alternate ways to deliver quality care to patients with diabetes," says DTT Editor-in-Chief Satish Garg, MD, Professor of Medicine and Pediatrics at the University of Colorado Denver (Aurora). "The study from UNC documented similar glycemic outcomes when transitioned to virtual care during the pandemic. It is important to note that the data presented is from finger-stick blood glucose values (FSBG). The smooth transition to virtual care may have long-term implications especially for remote area consults where endocrinologists may not be available. The real unknown is if the payors will continue similar reimbursements after COVID is gone. The FDA recently authorized use of continuous glucose monitoring (CGM) for the inpatient setting, and UNC authorized for hospital inpatient use of CGM only last week. I believe authors are in the process of implementing the use of CGM for inpatient diabetes management."

A low-pressure area designated as System 90L appears to be developing in the Straits of Florida, located between Southern Florida and Cuba. NASA's Aqua satellite measured cloud top temperatures within the developing system and found some stronger storms.

At 8:50 a.m. EDT on May 15, NOAA's National Hurricane Center (NHC) issued a Special Tropical Weather Outlook issued to discuss the potential for tropical or subtropical development near the northwest Bahamas.

The Outlook stated, "A trough (elongated area) of low pressure located over the Straits of Florida continues to produce disorganized shower activity and gusty winds across the Florida Keys, portions of southeast Florida, and the northwestern Bahamas. Gradual development of this system is expected, and it will likely become a tropical or subtropical storm on Saturday [May 16] when it is located near the northwestern Bahamas. Later in the weekend and early next week, the system is expected to move generally northeastward over the western Atlantic (Ocean)."

NASA's Aqua satellite provided information to NHC forecasters. One kind of data Aqua provides is infrared light to analyze the strength of storms by providing temperature information about the system's clouds. The strongest thunderstorms that reach high into the atmosphere have the coldest cloud top temperatures.

On May 15 at 3:45 a.m., EDT (0745 UTC) the Moderate Resolution Imaging Spectroradiometer or MODIS instrument that flies aboard NASA's Aqua satellite gathered infrared data on 90L. Strongest thunderstorms had cloud top temperatures as cold as minus 50 degrees Fahrenheit (minus 45.5 Celsius). As cloud tops continue to cool, they stretch higher into the troposphere. NASA research has shown that when cloud top temperatures drop to minus 70 degrees Fahrenheit (minus 56.6 degrees Celsius), storms have the ability to generate heavy rain.

The NHC Outlook stated, "Regardless of development, the disturbance will continue to bring heavy rainfall to portions of the Florida Keys, southeast Florida and the Bahamas through Saturday. Tropical storm-force wind gusts are also possible across portions of the Florida Keys, southeast Florida, and the Bahamas during the next day or so. In addition, hazardous marine conditions are expected along the Florida east coast and in the Bahamas where Gale Warnings are in effect. Dangerous surf conditions and rip currents are possible along portions of the southeast U.S. coast this weekend and early next week."

The NHC said that the formation chance through 48 hours and out through 5 days is high.

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

In designing electronic devices, scientists look for ways to manipulate and control three basic properties of electrons: their charge; their spin states, which give rise to magnetism; and the shapes of the fuzzy clouds they form around the nuclei of atoms, which are known as orbitals.

Until now, electron spins and orbitals were thought to go hand in hand in a class of materials that's the cornerstone of modern information technology; you couldn't quickly change one without changing the other. But a study at the Department of Energy's SLAC National Accelerator Laboratory shows that a pulse of laser light can dramatically change the spin state of one important class of materials while leaving its orbital state intact.

The results suggest a new path for making a future generation of logic and memory devices based on "orbitronics," said Lingjia Shen, a SLAC research associate and one of the lead researchers for the study.

"What we're seeing in this system is the complete opposite of what people have seen in the past," Shen said. "It raises the possibility that we could control a material's spin and orbital states separately, and use variations in the shapes of orbitals as the 0s and 1s needed to make computations and store information in computer memories."

The international research team, led by Joshua Turner, a SLAC staff scientist and investigator with the Stanford Institute for Materials and Energy Science (SIMES), reported their results this week in Physical Review B Rapid Communications.

An intriguing, complex material

The material the team studied was a manganese oxide-based quantum material known as NSMO, which comes in extremely thin crystalline layers. It's been around for three decades and is used in devices where information is stored by using a magnetic field to switch from one electron spin state to another, a method known as spintronics. NSMO is also considered a promising candidate for making future computers and memory storage devices based on skyrmions, tiny particle-like vortexes created by the magnetic fields of spinning electrons.

But this material is also very complex, said Yoshinori Tokura, director of the RIKEN Center for Emergent Matter Science in Japan, who was also involved in the study.

"Unlike semiconductors and other familiar materials, NSMO is a quantum material whose electrons behave in a cooperative, or correlated, manner, rather than independently as they usually do," he said. "This makes it hard to control one aspect of the electrons' behavior without affecting all the others."

One common way to investigate this type of material is to hit it with laser light to see how its electronic states respond to an injection of energy. That's what the research team did here. They observed the material's response with X-ray laser pulses from SLAC's Linac Coherent Light Source (LCLS).

One melts, the other doesn't

What they expected to see was that orderly patterns of electron spins and orbitals in the material would be thrown into total disarray, or "melted," as they absorbed pulses of near-infrared laser light.

But to their surprise, only the spin patterns melted, while the orbital patterns stayed intact, Turner said. The normal coupling between the spin and orbital states had been completely broken, he said, which is a challenging thing to do in this type of correlated material and had not been observed before.

Tokura said, "Usually only a tiny application of photoexcitation destroys everything. Here, they were able to keep the electron state that is most important for future devices - the orbital state - undamaged. This is a nice new addition to the science of orbitronics and correlated electrons."

Much as electron spin states are switched in spintronics, electron orbital states could be switched to provide a similar function. These orbitronic devices could, in theory, operate 10,000 faster than spintronic devices, Shen said.

Switching between two orbital states could be made possible by using short bursts of terahertz radiation, rather than the magnetic fields used today, he said: "Combining the two could achieve much better device performance for future applications." The team is working on ways to do that.

RIVERSIDE, Calif. -- An international research team led by scientists at the University of California, Riverside, has observed light emission from a new type of transition between electronic valleys, known as intervalley transmissions.

The research provides a new way to read out valley information, potentially leading to new types of devices.

Current semiconductor technology uses electronic charge or spin to store and process information; the associated technologies are called electronics and spintronics, respectively. Some semiconductors contain local energy valleys in their electron band structure that can be used to encode, process, and store information, giving rise to a new kind of technology called valleytronics.

"Valleytronics provides an alternative route to engineer information systems besides the conventional electronics and spintronics," said Chun Hung "Joshua" Lui, an assistant professor in the Department of Physics and Astronomy at UC Riverside, who led the research on intervalley transitions in monolayer tungsten diselenide (WSe2). "Our new work can speed up the development of valleytronics."

Monolayer WSe2 is a promising valleytronic material because it possesses two valleys with opposite dynamic characteristics in the band structure. Moreover, this material can interact strongly with light, holding promise for optically controllable valleytronic applications.

Excitons

When monolayer WSe2 absorbs a photon, a bound electron can be freed in a valley, leaving behind an electron vacancy, or hole. As the hole behaves like an electron with positive charge, the electron and hole can attract each other to form a bound state called an exciton. Such an exciton, with both its electron and hole in the same valley, is called an intravalley exciton. Current exciton research in monolayer valley semiconductors focuses predominantly on intravalley excitons, which can emit light.

An electron and a hole in opposite valleys can also form an exciton, called an intervalley exciton, which is a novel component in valleytronics. The law of momentum conservation, however, forbids an electron and a hole in opposite valleys from recombining directly to emit light. As a result, intervalley excitons are "dark" and hidden in the optical spectrum.

The UCR-led research team has now observed light emission from intervalley excitons in monolayer WSe2. The team found that although the intervalley excitons are intrinsically dark, they can emit a significant amount of light with the assistance of either defects or lattice vibrations in the material.

"The scattering with defects or lattice vibrations can compensate for the momentum mismatch between an electron and a hole in opposite valleys," Lui said. "It allows us to observe the light emission of intervalley excitons."

"Although the process involves scattering with defects or lattice vibrations, the intervalley light emission is circularly polarized," said Erfu Liu, a postdoctoral researcher in Lui's lab and the first author of the research paper. "Such circular light polarization allows us to identify the exciton valley configuration. This optically readable valley configuration is crucial to making intervalley excitons useful for valleytronic applications."

Trions

Besides the excitons, monolayer WSe2 also hosts trions, which consist of two electrons and one hole or two holes and one electron. Trions also have well-defined valley configurations for valleytronic applications. Compared to the charge-neutral excitons, the motion of trions can be controlled by an electric field due to their net electrical charge.

A trion can generally decay through two paths. For example, for a trion consisting of an intravalley electron-hole pair and a hole in the opposite valley to decay, the electron can choose to recombine with the hole in the same valley or with the hole in the opposite valley. This gives rise to two different trion decay paths with intravalley and intervalley electron-hole recombination. The intravalley trion decay has been much studied, but the intervalley trion decay has not been reported thus far.

The UCR-led team has shown intervalley trion decay for the first time.

"Although a trion can decay through either intravalley or intervalley decay, the two transitions have the same energy and can hardly be distinguished in the optical spectrum," Lui said. "But when a magnetic field is applied, the energies of the intravalley and intervalley transitions will become different."

The team carried out the experiments at the National High Magnetic Field Laboratory in Tallahassee, Florida. They show both the intravalley and intervalley decay paths of the trions.

"Our results provide a more complete, multipath picture of trion dynamics in monolayer WSe2," said Jeremiah van Baren, a graduate student in Lui's lab, who shares equal authorship with Liu. "They build on the existing single-path description of trions in 2-D materials and are key to furthering trion-based valleytronic science and technology."

The research paper, published in Physical Review Letters, is titled "Multipath optical recombination of intervalley dark excitons and trions in monolayer WSe2." Related results were recently reported by two other research teams led by scientists at Rensselaer Polytechnic Institute and the University of Washington.

After Tropical Cyclone Vongfong made landfall in the Philippines early on May 14 and began tracking through the country, imagery from NASA-NOAA's Suomi NPP satellite showed the storm was weakening.

On May 14, 2020, Typhoon Vongfong became the first typhoon of the 2020 West Pacific season. It came ashore as a typhoon and by May 15, it had weakened to a tropical storm.

On May 14, NOAA-20 satellite imagery showed features that one would expect from a tropical system, including overshooting tops and tropospheric gravity waves. On May 14 at 1:34 p.m. EDT (1734 UTC), "NASA-NOAA's Suomi NPP infrared satellite imagery showed the eye has now closed and convection has diminished within the eastern semicircle of the system, evident in the warming cloud tops," said William Straka III of the University of Wisconsin-Madison, who created night-time and infrared images. "The diminished convection could also be seen in imagery as compared to yesterday, where convection completely surrounded the circulation."

The nighttime image also showed a lightning streak on one of the southern feeder bands around Vongfong's center. The imagery also showed that the circulation was not surrounded by convection (thunderstorms). The surface rain product showed potentially some clear air (no rain) intruding into the circulation. "The 88.0 GHz ATMS imagery from the Suomi-NPP satellite, while at lower resolution, did not show a circulation surrounded by convection. Rather, it showed just cold temperatures in the northeastern part of the storm where the convection was located," Straka said.

On May 15 at 5 a.m. EDT (0900 UTC), Tropical storm Vongfong (Philippines designation Ambo) was located near latitude 14.1 degrees north and longitude 121.9 degrees east, about 60 nautical miles east-southeast of Manila, Philippines. Vongfong was moving to the northwest and had maximum sustained winds 60 knots (69 mph/111 kph).

Because of the impacts to the Philippines, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) are also tracking Typhoon Vongfong, which is called Ambo by PAGASA, to assess the impacts on the various islands in the path of the storm.

On May 15, PAGASA still had many warnings in effect, especially for the northern region of the Philippines as Vongfong moves through that area. Tropical cyclone wind signal number 2 is in effect for Luzon: that includes Ilocos Norte, Ilocos Sur, Apayao, Abra, Kalinga, La Union, Ifugao, Mountain Province, Benguet, Nueva Vizcaya, Quirino, Tarlac, Nueva Ecija, Aurora, Pampanga, Bulacan, Rizal, Metro Manila, Laguna, the eastern portion of Pangasinan, the western portion of Isabela, Cavite, Quezon including Pollilo Islands, Camarines Norte, western portion of Camarines Sur , Marinduque, and Batangas. Tropical cyclone wind signal number 1 is in effect for Luzon: Cagayan including Babuyan Islands, Batanes, the rest of Pangasinan, Zambales, Bataan, Oriental Mindoro, Burias Island, the rest of Camarines Sur, the rest of Isabela, and the northern portion of Albay.

Vongfong will continue to move northwest across the island of Luzon and is forecast to turn northeast and become extra-tropical.

WOODS HOLE, Mass. -- More carbon is stored in the forests, peatlands, and lakes of the high northern (boreal) latitudes than is currently in the atmosphere. Therefore, understanding how the boreal latitudes, which include Canada and Alaska, respond to global warming is very important for predicting its trajectory. As the climate warms, the air gets drier and can take up more water. The pines, spruces, and larches of boreal forests respond by largely retaining their water, but it hasn’t been known how boreal peatlands (bogs and fens) respond.

To compensate, a team of 59 international scientists, including Inke Forbrich of the Marine Biological Laboratory, pooled their data and discovered boreal peatlands lose more water than do forests in response to drying air. This has important implications not only for projections of water availability in these regions but for global carbon-climate feedbacks. With a lower water table, peatlands are more likely to release CO2 to the atmosphere, which in turn would accelerate the pace of global warming.

Most current global climate models assume the boreal region consists only of forest ecosystems. Adding peatlands data will improve their projections. Led by scientists at Canada’s McMaster University, the team published their report this week in Nature Climate Change.

Over the last 20 years, the rapid development of digital communication technology has given rise to new forms of social interaction on social media. Digital communication technologies can overcome physical, social and psychological barriers in building romantic relationships. Around 1400, dating sites/chats have been created over the last decade in North America alone. Solely in the UK, 23% of Internet users have met someone online with whom they had a romantic relationship for a certain period and that even 6% of married couples met through the web.

While communication technologies have revolutionized, and continue to revolutionize, the modalities of interaction and the building of emotional attachment on the one hand, on the
other, the online dating industry has given rise to new forms of pathologies and crime. Online romance scams are a modern form of fraud that have spread in Western societies along with the development of social media. Through a fictitious Internet profile, the scammer develops a romantic relationship with the victim for 6-8 months, building a deep emotional bond with the aim of extorting economic resources in a manipulative dynamic. There are two notable features: on the one hand, the double trauma of losing money and a relationship, on the other, the victim's shame upon discovery of the scam, an aspect that might lead to underestimation of the number of cases. Sixty-three percent of social media users and 3% of the general population report having been a victim at least once. Women, middle-aged people, and individuals with higher tendencies to anxiety, romantic idealization of affective relations, impulsiveness and susceptibility to relational addiction are at higher risk of being victims of the scam. Understanding the psychological characteristics of victims and scammers will allow at-risk personality profiles to be identified and prevention strategies to be developed.

This article is open access and can be obtained from the following link: https://benthamopen.com/FULLTEXT/CPEMH-16-24

Researchers have developed an AI algorithm that can detect and identify different types of brain injuries.

The researchers, from the University of Cambridge and Imperial College London, have clinically validated and tested the AI on large sets of CT scans, and found that it was successfully able to detect, segment, quantify and differentiate different types of brain lesions.

The results, reported in The Lancet Digital Health, could be useful in large-scale research studies, for developing more personalised treatments for head injuries and, with further validation, could be useful in certain clinical scenarios, such as those where radiological expertise is at a premium.

Head injury is a huge public health burden around the world and affects up to 60 million people each year. It is the leading cause of mortality in young adults. When a patient has had a head injury, they are usually sent for a CT scan to check for blood in or around the brain, and to help determine whether surgery is required.

"CT is an incredibly important diagnostic tool, but it's rarely used quantitatively," said co-senior author Professor David Menon, from Cambridge's Department of Medicine. "Often, much of the rich information available in a CT scan is missed, and as researchers, we know that the type, volume and location of a lesion on the brain are important to patient outcomes."

Different types of blood in or around the brain can lead to different patient outcomes, and radiologists will often make estimates in order to determine the best course of treatment.

"Detailed assessment of a CT scan with annotations can take hours, especially in patients with more severe injuries," said co-first author Dr Virginia Newcombe, also from Cambridge's Department of Medicine. "We wanted to design and develop a tool that could automatically identify and quantify the different types of brain lesions so that we could use it in research and explore its possible use in a hospital setting."

The researchers developed a machine learning tool based on an artificial neural network. They trained the tool on more than 600 different CT scans, showing brain lesions of different sizes and types. They then validated the tool on an existing large dataset of CT scans.

The AI was able to classify individual parts of each image and tell whether it was normal or not. This could be useful for future studies in how head injuries progress, since the AI may be more consistent than a human at detecting subtle changes over time.

"This tool will allow us to answer research questions we couldn't answer before," said Newcombe. "We want to use it on large datasets to understand how much imaging can tell us about the prognosis of patients."

"We hope it will help us identify which lesions get larger and progress, and understand why they progress, so that we can develop more personalised treatment for patients in future," said Menon.

While the researchers are currently planning to use the AI for research only, they say with proper validation, it could also be used in certain clinical scenarios, such as in resource-limited areas where there are few radiologists.

In addition, the researchers say that it could have a potential use in emergency rooms, helping get patients home sooner. Of all the patients who have a head injury, only between 10 and 15% have a lesion that can be seen on a CT scan. The AI could help identify these patients who need further treatment, so those without a brain lesion can be sent home, although any clinical use of the tool would need to be thoroughly validated.

The ability to analyse large datasets automatically will also enable the researchers to solve important clinical research questions that have previously been difficult to answer, including the determination of relevant features for prognosis which in turn may help target therapies.

Scientists from the Walter Reed Army Institute of Research joined partners at Duke University, Florida Atlantic University and Montana State University to publish a study providing clear evidence that malaria's characteristic cycle of fever and chills is a result of the parasite's own influence--not factors from the host.

What regulated that cycle, the result of parasites bursting out of infected red blood cells in sync then re-colonizing new red blood cells, has been studied since at least the 1920s. In the current study, evidence challenges the central dogma that a cyclic pattern of parasite growth is solely dependent on cues from the host.

Though the specific signals utilized remain to be elucidated, these findings raise the exciting possibility of disrupting this cycle as an antimalarial strategy.

"The malaria parasite contains an intrinsic biological oscillator that controls growth and development. Understanding the complex network that controls this oscillator could lead the development of novel antimalarials that may either kill the parasite or interfere with the growth cycle giving the host immune system the upper hand" said Colonel Norman Waters, an author on the paper.

In this study researchers studied four strains of Plasmodium falciparum, the deadliest and most prevalent of the five malaria species that infect humans, using in vitro cultures away from any host's circadian signals.

Using high-density time-series transcriptomics--techniques that measure the products of genes to gain insight into their activity--and microscopy, they found that the majority (87-92%) of tracked genes were cyclical--strong evidence that the cycle's primary regulator is intrinsic.

Malaria, infecting approximately 228 million individuals in 2018, remains a meaningful threat to public health and global stability. One of the top five infectious disease threats to deployed Service Members, WRAIR has participated in the development of most FDA-approved malaria prevention and treatment drugs as well as the world's most advanced malaria vaccine, RTS,S.

WRAIR and its partners remain committed to developing novel interventions to prevent the transmission of malaria, including mosquito repellents, chemoprophylaxis, biologics and more in order to eliminate the threat towards Service Members.

Berkeley -- For predators like wolves, cougars and snow leopards, a cow or sheep out to pasture may make for an easy and tasty meal. But when wild animals eat livestock, farmers face the traumatic loss of food or income, frequently sparking lethal conflicts between humans and their carnivorous neighbors.

Humans have struggled to reduce the loss of livestock to carnivores for thousands of years, and yet, solutions remain elusive. According to a new study led by researchers at the University of California, Berkeley, solving this ancient puzzle requires going back to Ecology 101.

Effectively reducing encounters between domestic prey and wild predators, the researchers argue, requires knowing the principles governing the ecological interactions among these players and their surrounding landscape. Simply put, getting in the mind of predators -- considering the ecology of how they hunt, how their prey behaves and how they interact with the landscape around them -- will help farmers and wildlife managers target interventions to discourage wild carnivores from preying on valuable livestock.

"There is no 'one-size-fits-all' solution for livestock predation, because the variables at play change, depending on the stakeholders, the landscape and the carnivores and livestock involved -- as well the scale and cost of management tools," said Christine Wilkinson, a graduate student in environmental science, policy and management at UC Berkeley and lead author on the study, which appeared this week in the journal Conservation Biology. "But at the core of the problem is an ecological act: predation."

In addition to lethal means of warding off potential predators, like poisoning or hunting, a variety of nonlethal deterrents are available. Guardian dogs, lights, electric fencing or bright-colored flags can all keep carnivores at bay while preserving the local ecology. Other strategies, like regularly moving livestock to different pastures or keeping them inside an enclosure at night, can make it harder for carnivores to locate and hunt them.

But the same techniques that prevent wolves from eating sheep in the rocky valleys of Idaho may not be as effective at preventing snow leopards from killing livestock in the high elevations of the Himalayas. Instead of focusing on the overall effectiveness of any one technique, the authors urge wildlife managers to approach the problem by considering a framework that includes the carnivore ecology, the livestock ecology and how the two species interact with the landscape around them.

"By knowing the full ecological story, we can tinker with the tools in our management toolkit to keep both predators and livestock safe," said Defenders of Wildlife senior scientist and co-author Jennie Miller.

For instance, wolves are known to be afraid of strings of red flags called fladry, and using fladry around a pasture might be a cost-effective method for keeping the predators away from sheep. But considering other aspects of the ecology, such as where the pastures are located, or where the sheep are kept at night, could yield even better results, depending on context.

These strategic combinations of deterrents have successfully kept predators at bay in a variety of settings, the paper points out. The authors highlight three case studies from around the world, demonstrating the success that can occur when ecology is the foundation of targeted interventions, and the failure that can occur when it is ignored.

The study's framework provides guidance for livestock managers to consider their management techniques as a component of livestock ecology. "Livestock have, in some sense, been bred to be an easy target for carnivores," Wilkinson said. "Humans have to recreate the defenses that we bred away."

The next step for

DALLAS – May 14, 2020 – The activity of the parasite that causes malaria is driven by the parasite’s own inherent clock, new research led by UT Southwestern scientists suggests. The findings, published this week in Science, could lead to new ways to fight this pervasive and deadly disease.

More than 200 million people contract malaria worldwide each year, and over 400,000 people die annually of this disease, according to statistics from the World Health Organization. Caused by protozoa in the genus Plasmodium, malaria kills mostly children, with the majority of deaths in sub-Saharan Africa.

It’s long been known that malaria induces cyclical fevers, which occur every two to three days in human hosts, depending on the species of infecting organism. This is the result of all the parasites simultaneously bursting the red blood cells of the host they infect.

“Together, these and other behavioral phenomena suggest that Plasmodium has a sense of time,” says study leader Joseph S. Takahashi, Ph.D., chair of neuroscience at UTSW and a Howard Hughes Medical Institute investigator. “But the reason for these daily rhythms has been mysterious.”

Although the prevailing theory has been that Plasmodium takes its cues from its animal hosts, Takahashi – who studies biological clocks – and his colleagues suspected that the parasite has its own internal clock that drives this behavior.

To investigate this hypothesis, Filipa Rijo-Ferreira, Ph.D., a postdoctoral research fellow and Howard Hughes Medical Institute associate who pioneered the project in the lab, worked with a mouse model of malaria infected by Plasmodium chabaudi. Like human patients, these animals also have cyclic fevers, about once per day.

To see whether the parasite’s rhythms are affected by light-dark cycles, which drive many circadian rhythms in humans and other animals, the researchers housed some infected mice in conditions that mimicked a regular day-night cycle, with 12 hours of light and 12 hours of darkness. Other mice were housed in complete darkness. For three days, the researchers collected blood from the animals and probed gene expression of their malaria parasites.

The researchers saw that of the 5,244 genes expressed by the blood stage of Plasmodium, more than 80 percent had the same cyclic patterns of expression in both lighting conditions. The activity of these genes peaked at the same time and with the same intensity in both groups, suggesting that the lighting cues that drive biological clocks in their mouse hosts weren’t affecting rhythms for the parasites.

To see if the clock in Plasmodium still ran about 24 hours, even if the clocks in their hosts do not, the researchers studied the parasite’s gene activity in mice with a genetic mutation that causes their own circadian rhythms to run about 26 hours instead of the usual 24. Tests showed that the protozoa seemed to slow their cell cycles to match those of their hosts, stretching them out to cover the 26-hour period. However, this correlation wasn’t perfect – Plasmodium’s gene expression lagged behind, taking several days to catch up with its long-period host. These findings suggest that although the parasite seems to take cues from its host, it still ran on its own time.

“This was a very exciting result since it was our first hint that parasites aren’t just following the host but could be able to tell time,” says Rijo-Ferreira. “We were on the right path.”

Further tests suggest that rhythmic feeding times – another external cue that drives biological rhythms in animals – also weren’t required for cyclical gene activity in Plasmodium. Similarly, these cycles persisted even in mouse hosts with mutations that completely obliterated their biological rhythms. However, in this latter case, the parasite’s rhythms gradually became dysregulated over time. These findings suggest that although individual parasites appear to be driven by their own biological clocks, they seem to need an external cue from their hosts to synchronize. Mathematical models that the researchers constructed support this idea.

Takahashi notes that further research will be necessary to confirm the parasite’s clocklike behavior. A companion study published in the same May 15 issue of Science, led by a group at Duke University, provides supporting evidence in humans. Identifying the mechanism behind this phenomenon, he says, could lead to new targets to attack malaria, either by disrupting its rhythms or by finding ways to capitalize on them by discovering points in the cycle when Plasmodium may be particularly vulnerable.

“This could add a whole new dimension to therapeutic treatment for this often fatal disease,” says Takahashi, a member of UT Southwestern’s Peter O’Donnell Jr. Brain Institute who holds the Loyd B. Sands Distinguished Chair in Neuroscience.

Miniature devices, notably those that bulge out from 2D surfaces like pop-up greeting cards, have seamlessly found their way into pressure-sensing and energy-harvesting technologies because of their ability to be frequently stretched, compressed or twisted. Despite their force-bearing abilities, it is still unclear if repeated physical stress can damage the working of these miniature devices, particularly if there is already a defect in their construction.

Using tiny pressure-sensing structures shaped like tables, Texas A&M University researchers have found that repeated pushes on the tables' flat surface do not cause the structures to fall apart, even when the compressive forces are extreme. Instead, these tiny devices, including those with slight defects, were resilient, continuing to remain functional by bending their legs in proportion to the applied force.

The researchers said their findings, published in the February issue of the journal Extreme Mechanics Letters, have direct implications on the longevity of technologies that incorporate miniature devices, like soft wearable electronics, stretchable solar cells and pressure-sensing socks.

Miniature devices, like pressure sensors, need to faithfully convey the strength and a change in compressions. For many applications, sensors need to be very small to capture changes in pressure at a high enough resolution. Thus, miniature devices based on the Japanese paper-cutting and folding technique of kirigami offer an excellent solution.

Borrowing the principles of kirigami, a design of the miniature device is first etched on a 2D surface. Then, an inward push from the design boundary makes the structure pop up. Other times, the 2D print is stretched or twisted to reveal a more intricate 3D design. Regardless of the final use, kirigami-based devices must face continuous distortions to their shape, a phenomenon engineers refer to as deformation.

"Part of the appeal of using kirigami structures is that they can be repeatedly deformed for extended periods of time," said Dr. Andreas A. Polycarpou, professor and department head in the J. Mike Walker '66 Department of Mechanical Engineering. "But any kind of imperfection in these structures might impact their final performance, that is, their ability to be continuously deformed."

To investigate how defects might influence the function of kirigami devices, Polycarpou's team, led by Kian Bashandeh, graduate student in the College of Engineering and a primary author of the study, designed a set of experiments using tiny pressure sensors. Consisting of a flat surface supported by four legs, these structures buckle if pressure is applied from above.

For their study, the researchers repeatedly pressed down on the table-like structures using a diamond flat punch probe. Their sample included structures with slight defects, such as a small crack on one of the four legs or one slightly thinner leg.

To test the performance of these structures over time, they recorded how these structures behaved under repeated compressions using an electron microscope and measured the distance by which the legs bent.

Polycarpou's team found that for both defect-free and defective kirigami structures, the compression caused the structures to "stiffen" or resist the downward force. Over time, however, even when compressive forces were extreme, the structures reached a steady-state and were able to recover from the repeated blows from the diamond punch.

The researchers said the results of their cyclic compression experiments suggest that systems with an assembly of kirigami devices can remain functional for a long period of time even if some of the devices within them have defects.

"For most applications, including pressure sensing, it's not one but multiple miniature devices working in tandem. Intuitively one would think that small defects in any one of the kirigami structures would be catastrophic for a system made with many of such structures," said Polycarpou. "We now have evidence to show that they do not. So, if one is using smart socks to measure how pressure is distributed during gait, our results suggest that the miniature pressure sensors will still work remarkably well even if they are slightly defective."

Skoltech researchers have offered a solution to the problem of searching for materials with required properties among all possible combinations of chemical elements. These combinations are virtually endless, and each has an infinite multitude of possible crystal structures; it is not feasible to test them all and choose the best option (for instance, the hardest compound) either in an experiment or in silico. The computational method developed by Skoltech professor Artem R. Oganov and his PhD student Zahed Allahyari solves this major problem of theoretical materials science. Oganov and Allahyari presented their method in the MendS code (stands for Mendelevian Search) and tested it on superhard and magnetic materials.

"In 2006, we developed an algorithm that can predict the crystal structure of a given fixed combination of chemical elements. Then we increased its predictive powers by teaching it to work without a specific combination -- so one calculation would give you all stable compounds of given elements and their respective crystal structures. The new method tackles a much more ambitious task: here, we pick neither a precise compound nor even specific chemical elements -- rather, we search through all possible combinations of all chemical elements, taking into account all possible crystal structures, and find those that have the needed properties (e.g., highest hardness or highest magnetization)" says Artem Oganov, Skoltech and MIPT professor, Fellow of the Royal Society of Chemistry and a member of Academia Europaea.

The researchers first figured out that it was possible to build an abstract chemical space so that compounds that would be close to each other in this space would have similar properties. Thus, all materials with peculiar properties (for example, superhard materials) will be clustered in certain areas, and evolutionary algorithms will be particularly effective for finding the best material. The Mendelevian Search algorithm runs through a double evolutionary search: for each point in the chemical space, it looks for the best crystal structure, and at the same time these found compounds compete against each other, mate and mutate in a natural selection of the best one.

To test the efficacy of the new method, scientists gave their machine a task to find the composition and structure of the hardest material. Their algorithm returned diamond, which makes pursuits for materials harder than diamond a dead end. Moreover, the algorithm also predicted several dozen hard and superhard phases, including most of the already known materials and several completely new ones.

This method can speed up the search for record-breaking materials and usher in new technological breakthroughs. Equipped with these materials, scientists can create brand new technologies or increase the efficiency and availability of old ones.