Computers Math

Researchers have discovered that light — in the form of a laser — can trigger a form of magnetism in a normally nonmagnetic material. This magnetism centers on the behavior of electrons. These subatomic particles have an electronic property called “spin,” which has a potential application in quantum computing. The researchers found that electrons within the material became oriented in the same direction when illuminated by photons from a laser.
The experiment, led by scientists at the University of Washington and the University of Hong Kong, was published April 20 in Nature.
By controlling and aligning electron spins at this level of detail and accuracy, this platform could have applications in the field of quantum simulation, according to co-senior author Xiaodong Xu, a Boeing Distinguished Professor at the UW in the Department of Physics and the Department of Materials Science and Engineering.
“In this system, we can use photons essentially to control the ‘ground state’ properties — such as magnetism — of charges trapped within the semiconductor material,” said Xu, who is also a faculty researcher with the UW’s Clean Energy Institute and the Molecular Engineering & Sciences Institute. “This is a necessary level of control for developing certain types of qubits — or ‘quantum bits’ — for quantum computing and other applications.”
Xu, whose research team spearheaded the experiments, led the study with co-senior author Wang Yao, professor of physics at the University of Hong Kong, whose team worked on the theory underpinning the results. Other UW faculty members involved in this study are co-authors Di Xiao, a UW professor of physics and of materials science and engineering who also holds a joint appointment at the Pacific Northwest National Laboratory, and Daniel Gamelin, a UW professor of chemistry and director of the Molecular Engineering Materials Center.
The team worked with ultrathin sheets — each just three layers of atoms thick — of tungsten diselenide and tungsten disulfide. Both are semiconductor materials, so named because electrons move through them at a rate between that of a fully conducting metal and an insulator, with potential uses in photonics and solar cells. Researchers stacked the two sheets to form a “moiré superlattice,” a stacked structure made up of repeating units. More

We blame smartphone use for a number of negative consequences, ranging from neck pain to addictive behavior. Privat-Dozentin Dr. Julia Brailovskaia and her team set out to determine whether our lives are actually better without smartphones, or rather: how much less smartphone use per day is good for us. The psychologist from the Mental Health Research and Treatment Center at Ruhr-Universität Bochum (RUB) had around 200 test participants each do without their smartphones completely for a week, reduce their daily use by one hour or use the smartphone in the same way as before. Their findings show: in the long term, those who reduced their use fared best. The researcher report in the Journal of Experimental Psychology: Applied from 7 April 2022.
How much smartphone use is good for us?
On average, we spend more than three hours a day glued to our smartphone screens. We google, look for directions, check emails or the weather, shop, read the news, watch films, hang out on social media. It seems reasonable to suspect that all this is not good for us. Studies have shown that smartphone use is linked to problems such as less physical activity, obesity, neck pain, impaired performance, and addiction-like behavior — to name just a few. “The smartphone is both a blessing and a curse,” says Julia Brailovskaia.
Her team wanted to know: how much smartphone is good for us? To this end, the researchers compared the effect of complete smartphone abstinence versus a reduction in time spent daily looking at the screen and versus continued use without any changes. They recruited 619 people for their study and divided them randomly into three groups. 200 people put their smartphone completely aside for a week. 226 reduced the amount of time they used the device by one hour a day. 193 people didn’t change anything in their behavior.
Physical activity, cigarettes, life satisfaction, anxiety, depression
The researchers interviewed all participants about their lifestyle habits and well-being immediately after the intervention, one month and four months later. How much did they engage in physical activity? How many cigarettes did they smoke a day? How satisfied with their life did they feel? Did they show any signs of anxiety or depression? “We found that both completely giving up the smartphone and reducing its daily use by one hour had positive effects on the lifestyle and well-being of the participants,” as Julia Brailovskaia sums up the results. “In the group who reduced use, these effects even lasted longer and were thus more stable than in the abstinence group.”
It’s not necessary to do completely without
The one-week intervention changed the participants’ usage habits in the long term: even four months after the end of the experiment, the members of the abstinence group used their smartphone on average 38 minutes less per day than before. The group who had spent one hour less per day with the smartphone during the experiment used it as much as 45 minutes less per day after four months than before. At the same time, life satisfaction and time spent being physically active increased. Symptoms of depression and anxiety as well as nicotine consumption decreased. “It’s not necessary to completely give up the smartphone to feel better,” concludes Brailovskaia. “There may be an optimal daily usage time.”
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Materials provided by Ruhr-University Bochum. Original written by Meike Drießen. Note: Content may be edited for style and length. More

Scientists have grown thin films of two different crystalline materials on top of each other using an innovative technique called “dative epitaxy.” The researchers discovered the method by surprise.
As University at Buffalo physicist Hao Zeng explains, dative epitaxy holds layers of different materials together via a weak attractive force between the materials, paired with occasional chemical bonds called “dative bonds.”
“I compare this to laying down wood floor in your home,” says Zeng, professor of physics in the UB College of Arts and Sciences. “You put a few nails in to anchor the wood planks on the surface. The dative bonds are like these nails.”
The research is exciting, Zeng says, because new ways to layer films “could have far-reaching impacts in the fields of semiconductors, quantum technology and renewable energy.”
Zeng and colleagues report on dative epitaxy in a March paper in Advanced Materials. The study was published by a team from the U.S., China and Singapore, led by Zeng, PhD, and Mengying Bian, PhD, at UB; Liang Zhu, PhD, and Junhao Lin, PhD, at the Southern University of Science and Technology; and Yanglong Hou, PhD, at Peking University.
A ‘fortuitous’ discovery
“We did not start with the idea of dative epitaxy,” Zeng says. “I would say it was a fortuitous discovery. Initially, we were trying to grow atomically thin magnets on a layer of van der Waals material, which acts as a template to promote 2D growth.” More

A new digital health study by researchers at Scripps Research shows how data from wearable sensors, such as smartwatches and fitness bands, can track a person’s physiological response to the COVID-19 vaccination.
The study, published in npj Digital Medicine, analyzed sensor data on sleep, activity and heart rate from over 5,600 individuals. Among the findings, the team showed that the average resting heart rate of participants significantly increased the day following vaccination. The effect appeared to be stronger after the second dose of the Moderna vaccine, compared to the Pfizer-BioNTech vaccine, and more pronounced in younger individuals.
According to lead author Giorgio Quer, PhD, director of Artificial Intelligence at the Scripps Research Translational Institute, this study is a first step toward quantifying the physiological response to vaccination in individuals using commercial sensors.
“Investigating the physiological signals in the period around vaccination can help us better understand the variability of vaccine response between people, as well as the changes from an individual norm due to vaccination,” Quer says. “As these individual changes are due to a person’s initial immune response to the vaccine, they can potentially help guide future vaccine development to optimize their efficacy and safety, and allow for more precise, individualized vaccine regimens.”
The researchers drew their data from a larger project, called Digital Engagement and Tracking for Early Control and Treatment (DETECT) launched in March 2020, in response to the emergence and rapid spread of SARS-CoV-2, the virus that causes COVID-19. DETECT is a mobile-app research platform that allows participants to share physiological and behavioral data gathered through a fitness band or smartwatch, as well as manually entered symptoms, test results and vaccination status.
To determine whether consumer wearables could unearth digital biomarkers of vaccine-induced immune response, the scientists analyzed DETECT sensor data from two weeks before and after each vaccination dose. They compared post-vaccination changes to the participants’ resting heart rate, sleep and activity levels, to their baselines. More

Dengue is the most widespread mosquito-borne disease in the world, and to date, there are no medical treatments for people suffering from this disease. The virus causes symptoms ranging from high fevers to severe bleeding and shock, can be life-threatening, and presents an enormous burden on health systems.
In Chaos, by AIP Publishing, researchers from Spain, Portugal, and Colombia developed a model the virus. In 2009, researchers discovered mosquitoes carrying Wolbachia bacteria lessen the chances for the dengue virus to impact humans.
Mosquitoes do not acquire Wolbachia bacteria in their natural environment, however. This bacterium must be introduced in vitro in mosquitoes’ eggs, which are later released in areas affected by dengue transmission. Mosquitoes infected with Wolbachia naturally take over the local mosquito population.
The researchers use real data on human and vector activity in a framework that can be analyzed from a mathematical point of view, allowing them to re-create and understand the epidemiological situation. In this way, they can identify those geographical areas with the greatest vulnerability, creating a ranking of areas that prioritizes those where Wolbachia-carrying mosquitoes can have the strongest and most beneficial impact on the spread of the dengue virus.
“One might think that the most populated areas are those in which Wolbachia release would be most beneficial. However, this is not always true,” said co-author Jesus Gomez-Gardenes, from Universidad del Valle in Colombia.
The authors found once they immunize the most vulnerable geographical area, the ranking of the remaining areas is affected, giving rise to a new scenario that tells them where they should concentrate resources in the second instance and beyond.
The findings from this research will be beneficial to many groups, such as the World Mosquito Program, which is currently releasing Wolbachia-infected mosquitoes to protect the global community from diseases such as dengue, chikungunya, yellow fever, and Zika.
In these kinds of initiatives, the information about the most vulnerable areas within cities or regions proved the researchers’ model could complement field studies to find targets that maximize the benefit for the whole community.
“Data-driven models have also proven useful to tackle the evolution and mitigation of other diseases such as COVID-19,” said Gomez-Gardenes. “Hopefully, the framework developed for dengue can be further generalized for tackling the control of other vector-borne diseases.”
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Materials provided by American Institute of Physics. Note: Content may be edited for style and length. More

Because of its outstanding transparency as well as its stability in contact with heat or chemicals, glass is relevant for many high-tech applications. However, conventional processes for shaping glass are often tedious, energy-intensive and quickly reach their limits for small and complicated components. The Freiburg materials scientists Dr. Frederik Kotz-Helmer and Prof. Dr. Bastian E. Rapp, in cooperation with the University of California at Berkeley in the US, have developed a novel process that can be used to produce very small components from transparent glass quickly and precisely using micro 3D printing. Possible applications include components for sensors and microscopes, but also for lab-on-a-chip systems. The researchers were able to publish their results in the current issue of the journal Science.
Glass powder in plastic binder
The new technology is based on so-called Glassomer materials, which Kotz-Helmer and Rapp developed at the Department of Microsystems Engineering (IMTEK) at the University of Freiburg. “Glassomer materials consist of glass powder in a special plastic binder,” says Kotz-Helmer, “allowing to process glass like a plastic.” The resulting components are then placed in a furnace, which causes the plastic to burn and the glass to be sintered, i.e. densified. “In the end, the components consist of one hundred percent highly transparent fused silica glass,” says Kotz-Helmer.
Component is created in a single step
The Freiburg scientists have now combined Glassomer materials with a new 3D printing process developed by a research team led by Prof. Dr. Hayden Taylor from the University of California, Berkeley. Conventional 3D printers print their objects layer by layer. However, in the new process, called Computed Axial Lithography (CAL), the component is created in a single step. A vessel containing liquid, light-sensitive material is exposed to two-dimensional light images of the object to be printed from many different angles. Where the images overlap and the amount of light absorbed thus locally exceeds a certain threshold, the material hardens abruptly — within a few minutes, the component is formed. The excess, still liquid material can be washed off.
Structures with the thickness of a single hair
“In principle, this process also works with Glassomer material,” says Kotz-Helmer. For this purpose, the Freiburg scientists developed a material made of glass powder and plastic that is both highly transparent and hardens quickly at a suitable threshold value. “The devil was in the chemical details here,” says the materials scientist. Previously, moreover, the CAL process had only been suitable for relatively coarse structures. By combining the materials science expertise at the University of Freiburg and the project partner Glassomer GmbH, a Freiburg spin-off, as well as the further development of the system technology at the University of California, it has now been possible to combine and improve these technologies. “For the first time, we were able to print glass with structures in the range of 50 micrometers in just a few minutes, which corresponds roughly to the thickness of a hair,” says Kotz-Helmer. “In addition, the surfaces of the components are smoother than with conventional 3D printing processes.”
Glass as a substitute for vulnerable plastic
Kotz-Helmer sees possible applications for the innovative manufacturing process, for example, in micro-optical components of sensors, virtual reality headsets and modern microscopes: “The ability to manufacture such components at high speed and with great geometric freedom will enable new functions and more cost-effective products in the future.”
Microfluidic channels are also needed for so-called lab-on-a-chip systems for research and medical diagnostics. Until now, these have mostly been made of plastics, but they often cannot withstand high temperatures and aggressive chemicals. Thanks to the new process technology, complex channel systems can now be manufactured in glass, says Kotz-Helmer: “Thanks to the thermal and chemical stability of glass, many new fields of application are opening up, especially in the area of chemistry on-a-chip synthesis.”
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Materials provided by University of Freiburg. Note: Content may be edited for style and length. More

If you become ill with COVID-19, your smartwatch can track the progression of your symptoms, and could even show how sick you become.
That’s according to a University of Michigan study that examined the effects of COVID-19 with six factors derived from heart rate data. The same method could be used to detect other diseases such as influenza, and the researchers say the approach could be used to track disease at home or when medical resources are scarce, such as during a pandemic or in developing countries. Their results are published in the journal Cell Reports Medicine.
Following U-M students and medical interns throughout the country, the researchers discovered new signals embedded in heart rate indicating when individuals were infected with COVID and how sick they became. The researchers found that individuals with COVID experienced an increase in heart rate per step after symptom onset, and those with a cough had a much higher heart rate per step than those without a cough.
“We found that COVID dampened biological timekeeping signals, changed how your heart rate responds to activity, altered basal heart rate and caused stress signals,” said Daniel Forger, professor of mathematics and research professor of computational medicine and bioinformatics. “What we realized was knowledge of physiology, how the body works and mathematics can help us get more information from these wearables.”
The researchers found that these measures were significantly altered and could show symptomatic vs. healthy periods in the wearers’ lives.
“There’s been some previous work on understanding disease through wearable heart rate data, but I think we really take a different approach by focusing on decomposing the heart rate signal into multiple different components to take a multidimensional view of heart rate,” said Caleb Mayer, a doctoral student in mathematics. More

A scientific team supported by the National Institutes of Health has created a tiny, bioengineered 3-D model that mimics the biology of chronic inflammatory demyelinating polyneuropathy and multifocal motor neuropathy, a pair of rare, devastating neuromuscular diseases. The researchers used the organ-on-a-chip, or “tissue chip,” model to show how a drug could potentially treat the diseases. They provided key preclinical data for a drug company to submit to the U.S. Food and Drug Administration to get authorization for testing in a clinical trial.
This work provides one of the first examples of scientists using primarily tissue chip data for an FDA Investigational New Drug application to test the efficacy of a candidate drug in people with rare diseases. The drug company Sanofi started recruiting participants into a Phase 2 clinical trial in April 2021. The drug was tested for safety previously and approved by the FDA for a different indication.
The tissue chip research was led by Hesperos, Inc., an Orlando-based company partially funded by a Small Business Innovation Research grant from NIH’s National Center for Advancing Translational Sciences (NCATS). This study could open the door to studying and developing new therapies for other rare diseases by establishing a new avenue for repurposing existing drugs for rare diseases. Most of the known 7,000 rare diseases do not have effective treatments. Researchers often lack animal models for studying rare disease biology and testing potential drugs.
“This marks an important milestone in the evolution of the use of tissue chips,” said Lucie Low, Ph.D., scientific program manager for the NCATS Tissue Chip for Drug Screening initiative. “We know that pharmaceutical companies are using tissue chips internally. Submitting data to regulatory agencies generated from tissue chip platforms is a powerful indicator of their growing promise.”
James Hickman, Ph.D., chief scientist at Hesperos, and his colleagues described the development of the model and their research results in Advanced Therapeutics. In these diseases, the immune system makes proteins called antibodies that damage nerve cells and slow down messages moving from the brain to the muscles. This can make it hard for people to move their arms, hands and legs. Current treatments can help, but often are inconsistent.
The researchers developed a tissue chip model consisting of two cell types: motoneurons and Schwann cells. Motoneurons transmit messages from the brain to muscles. Schwann cells help the signals move more quickly. The model could mimic functional characteristics of the diseases, allowing the scientists to see how a drug was working by determining whether the brain’s messages to muscles were slowing down or not.
The researchers showed that exposing the cells to blood serum from people with these rare diseases caused a shower of immune system antibodies against the cells. This made the motoneuron signals move more slowly. After treatment with TNT005, a drug that blocks the immune system reaction, the cells and the message speed returned to normal.
“We’re confident that our system can reproduce what happens to a patient, including the disease symptoms and disease progression,” said Hickman. “It’s important to create functionally relevant patient models that will mimic what is seen in clinical trials.”
Approximately 90% of promising therapies fail in clinical trials because animal models used in preclinical testing are not good at predicting how people will respond. To improve that success rate and help get more treatments to people who have few options, scientists are exploring the uses of tissue chips. Designed to support living human tissues and cells, tissue chips mimic the structure and function of human organs and systems, such as the lungs, heart and liver. Researchers are studying their uses in many areas, including for testing the safety and effectiveness of candidate drugs and modeling diseases.
The potential clinical uses of tissue chip data are growing. Recently, an NIH-supported research team at Harvard University’s Wyss Institute reported using a tissue chip model to generate data on the effectiveness of a repurposed drug for treating lung damage from COVID-19 infection. In the NCATS-funded Clinical Trials on a Chip program, several projects examine how tissue chip data can help researchers design more useful clinical trials. This might include using such data to predict which patients in a trial are most likely to respond to a therapy.
“Creating a platform that can predict human responses to a drug in a rare disease could lead to exciting new opportunities in research,” said Low. “If tissue chip data can be generated that inform the decisions made before early human trials, this could reduce the risks to vulnerable populations.”
Funding for this research was provided by True North Therapeutics (now Sanofi), NCATS (SBIR 2R44TR001326-03) and internal Hesperos development funds. More