Understanding living systems, such as tissues formed by cells, poses a significant challenge because of their unique properties, such as adaptation, self-repair and self-propulsion. Nonetheless, they can be studied using models that treat them as just an unusual, “active” form of physical matter. This can reveal extraordinary dynamical or mechanical properties. One of the puzzles is how active materials behave under shear (the deformation produced by moving the top and bottom layers sideways in opposite directions, like sliding microscope cover plates against each other). Researchers at the Institute for Theoretical Physics, University of Göttingen explored this question and discovered a novel type of ordering effect that is generated and sustained by steady shear deformation. The researchers used a computer model of self-propelling particles where each particle is driven by a propulsion force that changes direction slowly and randomly. They found that while the flow of the particles looks similar to that in ordinary liquids, there is a hidden order revealed by looking at the force directions: these tend to point towards the nearest (top or bottom) plate, while particles with sideways forces aggregate in the middle of the system.

“We were exploring the response of a model active material under steady driving, where the system is sandwiched between two walls, one stationary and the other moving to generate shear deformation. What we saw was that at a sufficiently strong driving force, an interesting ordering effect emerges,” comments Dr Rituparno Mandal, Institute for Theoretical Physics at the University of Göttingen. “We now also understand the ordering effect using a simple analytical theory and the predictions from this theory match surprisingly well with the simulation.”

Senior author Professor Peter Sollich, also from the Institute for Theoretical Physics, Universiy of Göttingen, explains, “Often an external force or driving force destroys ordering. But here the driving by shear flow is key in providing mobility to the particles that make up the active material, and they actually need this mobility to achieve the observed order. The results will open up exciting possibilities for researchers investigating the mechanical responses of living matter.”

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Materials provided by University of Göttingen. Note: Content may be edited for style and length.

“The findings suggest that pediatricians and other primary care providers could use the device to catch amblyopia at an early age when it’s easier to treat,” said Michael F. Chiang, M.D., director of the National Eye Institute (NEI), which supported research and development of the device. NEI is part of the National Institutes of Health.

Amblyopia is impaired vision in one eye and it is the leading cause of preventable monocular (single eye) vision loss, affecting three of every 100 children in the U.S.

During early childhood, our developing brains learn how to take images from each eye and fuse them into a single image to produce vision. Amblyopia develops when misalignment of the eyes (strabismus) or decreased acuity in one eye interferes with the brain’s ability to process visual information from both eyes, causing it to favor one eye. Once a child is visually mature, vision lost in the weaker eye cannot be corrected with glasses or contact lenses.

Children with amblyopia can suffer from poor school performance and impairments in depth perception and fine motor skills such as handwriting and other hand-eye coordinated activities.

Treatment of amblyopia generally involves placing a patch over the good eye to improve vision in the weaker eye. Patching is less successful as children get older, making early detection crucial. However, this depends on timely diagnosis by the child’s doctor, and most pediatricians are equipped only for basic eye chart vision screening tests, which are not useful for detecting amblyopia in very young children.

The screening device works by assessing the eyes’ ability to fixate together. Held 14 inches from the eyes, the child fixates on a smiley face while the device simultaneously scans both retinas. The scan involves a polarized laser that probes nerve fibers in an area of the light-sensing retina called the fovea, which is important for central vision. Even a subtle misalignment of the foveas — called small-angle strabismus — can interfere with the brain’s ability to integrate images from both eyes. The device calculates a binocularity score that indicates whether the child requires referral to an eye health physician for further investigation.

For the study, 300 children, ages 2 to 6 years, with no known eye disorders were recruited during previously scheduled visits to two Kaiser Permanente Southern California pediatric clinics.

Two non-ophthalmic research associates who were trained how to use the device screened each child, and the results were compared against those from an eye examination performed by a pediatric ophthalmologist who was unaware of the device’s results. The device detected all six cases (100% sensitivity) of amblyopia and/or strabismus that had been confirmed by the professional eye examination. The device also flagged an additional 45 children as possibly having amblyopia and/or strabismus who were later determined by the eye examination to be normal (85% specificity).

“In the hands of a trained user, it takes 28 seconds to sit the child down, perform the test, and record the results — provided that the child cooperates — which is an important consideration for its adoption in busy pediatric care settings,” said the study’s co-lead investigator, Shaival S. Shah, M.D., a pediatric ophthalmologist at Kaiser Permanente based in Tustin Ranch, California. The test itself requires just 2.5 seconds of a child’s attention.

A key limitation of the study was that the device was not compared with currently available photo-screening devices. Such devices detect differences in light reflexes in each eye and produce images that can help detect risk factors for amblyopia, but not amblyopia itself, which can result in both over and under detection of amblyopia.

By contrast, the pediatric vision scanner detects the presence of amblyopia as opposed to the risk factors of amblyopia, which may lead to fewer unnecessary referrals to pediatric ophthalmologists.

The pediatric vision screener tested in the study is a prototype of blinq. ®, a device that was cleared by the U.S. Food and Drug Administration in 2016.

The clinical trial identifier is NCT02536963. The study was supported by NEI grant R44EY025926 to Rebiscan, Inc. (doing business as Rebion), the Boston-based firm that markets blinq.®. Support was provided under the Small Business Innovation Research (SBIR) program, a funding mechanism that helps independently owned companies with 500 or fewer employees bring biomedical technologies to the market.

Co-founder of Rebion, David Hunter, M.D., Ph.D., ophthalmologist-in-chief at Boston Children’s Hospital, co-invented blinq.® with support from NEI grant R01EY012883.

Since 2015, scientists of the Leibniz-IZW Cheetah Research Project (CRP) conduct a National Cheetah Survey together with the Namibian Ministry of Environment, Forestry and Tourism (MEFT). The purpose is to obtain data on cheetah density and distribution across the country. Within this framework, a coalition of three cheetah males was captured in the Namib Desert and one animal equipped with a GPS collar. The recorded location and movement data were regularly downloaded during aerial tracking flights. On one of these flights, on October 5^th 2019, the carcass of a collared cheetah — one of the members of the coalition — was located from the aircraft. During the following ground inspection, the other two cheetahs were also found dead. “The GPS data of the collared cheetah revealed that they died within a time window of six hours a few days before we found them,” says Ruben Portas, CRP scientist. “Evaluating their most recent movements, we identified a cluster of GPS locations approximately two kilometres away from the location where they were found dead.” At this spot the cheetahs spent 20 hours on the day before their death. When visiting this cluster, Portas found the carcass of an adult mountain zebra. The GPS and activity data from the collar suggested that the cheetahs fed on it. Bacillus anthracis, the cause of Anthrax infections, was isolated from buccal and nasal swabs collected from the dead zebra, making it the first confirmed anthrax infection in a wildlife species in the Namib Desert.

Carnivores are typically less susceptible to anthrax than herbivores. Cheetahs in particular have a high constitutive innate immunity which provides them with a rapid first line of defence against pathogens such as Bacillus anthracis. “However, when a high load of bacteria is ingested, for example with meat from a contaminated carcass, their potent constitutive innate immunity might be overloaded,” explains CRP project head Bettina Wachter. “Cheetahs scavenge only rarely, which reduces their exposure to anthrax infected prey. As a result, they do not produce high antibody titres, which would be another line of defence. Thus, cheetahs die quickly when infected, as studies in Etosha National Park in northern Namibia have shown.”

The pathogen was not detected in any of the three cheetahs found in the Namib, but the scientists consider it very likely that anthrax was the direct cause of their death. Bacterial cultures from highly susceptible animals that quickly die are often anthrax negative, because the animals might die already at a low presence of bacteria in the blood or from a high load of toxin released by Bacillus anthracis when destroyed by the immune system. Additionally, the vegetative form of the pathogen only develops when exposed to air quickly after the death of the host. The cheetahs were untouched for 11 days after their death and their bodies were not opened by scavengers, which might also explain the negative results of the lab tests for anthrax.

Anthrax is an unstudied disease in arid habitats. When wildlife dies in the Namib Desert, causes are often attributed to drought, hunger and the challenging desert conditions. “The few reported cases in which diseases such as anthrax were tested in the arid environments of Namibia are when livestock or people were directly affected,” says Portas. “We do not know the prevalence of anthrax in the Namib desert and how wildlife populations are affected by the disease. For other habitats, such as the Etosha National Park, there is a large body of research showing that anthrax has a key ecological role in the environment.”

This first confirmed case of anthrax in the Namib Desert in wildlife demonstrates that the disease might by endemic in the desert and other arid environments. Most of the Namib Desert is included in protected areas where cheetahs and other species find an important refuge from conflict with humans. Thus, this new knowledge may be important for assessing risks to the species. “Although few data are available, no other disease has shown such an impact on the cheetah population and certainly requires further research that may lead to appropriate conservation measures,” Wachter concludes. “This study shows that data recorded by GPS collars have the potential to disclose additional important information in addition to spatial movement information.”

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Materials provided by Leibniz Institute for Zoo and Wildlife Research (IZW). Note: Content may be edited for style and length.

According to the study, published in Drug and Alcohol Dependence, which evaluated the feasibility of using smartphone sensor data to identify episodes of cannabis intoxication in the natural environment, a combination of time features (tracking the time of day and day of week) and smartphone sensor data had a 90 percent rate of accuracy.

“Using the sensors in a person’s phone, we might be able to detect when a person might be experiencing cannabis intoxication and deliver a brief intervention when and where it might have the most impact to reduce cannabis-related harm,” said corresponding author, Tammy Chung, professor of psychiatry and director of the Center for Population Behavioral Health at the Rutgers Institute for Health, Health Care Policy and Aging Research.

Cannabis intoxication has been associated with slowed response time, affecting performance at work or school or impairing driving behavior leading to injuries or fatalities. Existing detection measures, such as blood, urine or saliva tests, have limitations as indicators of cannabis intoxication and cannabis-related impairment in daily life.

The researchers analyzed daily data collected from young adults who reported cannabis use at least twice per week. They examined phone surveys, self-initiated reports of cannabis use, and continuous phone sensor data to determine the importance of time of day and day of week in detecting use and identified which phone sensors are most useful in detecting self-reported cannabis intoxication.

They found that time of day and day of week had 60 percent accuracy in detecting self-reporting of cannabis intoxication and the combination of time features and smartphone sensor data had 90 percent accuracy in detecting cannabis intoxication.

Travel patterns from GPS data — at times when they reported feeling high — and movement data from accelerometer that detects different motions, were the most important phone sensor features for detection of self-reported cannabis intoxication.

Researchers used low burden methods (tracking time of day and day of week and analyzing phone sensor data) to detect intoxication in daily life and found that the feasibility of using phone sensors to detect subjective intoxication from cannabis consumption is strong.

Future research should investigate the performance of the algorithm in classifying intoxicated versus not intoxicated reports in those who use cannabis less frequently. Researchers should study reports of intoxication using tools that law enforcement might use showing a stronger correlation with self-reported cannabis use.

Study authors include faculty from Stevens Institute of Technology, Stanford University, Carnegie Mellon University, University of Tokyo, Japan, and University of Washington, Seattle.

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Materials provided by Rutgers University. Original written by Nicole Swenarton. Note: Content may be edited for style and length.

Scientists have previously created superfluids in liquids, solids, and gases, and hope harnessing superfluids’ properties could help lead to discoveries such as a superconductor that works at room temperature. Bhattacharya said such a discovery could revolutionize the electronics industry, where loss of energy due to resistive heating of wires incurs major costs.

However, one of the main problems with studying superfluids is that all available methods of measuring the delicate superfluid rotation bring the motion to a halt. Bhattacharya and his team of RIT postdoctoral researchers teamed up with scientists in Japan, Taiwan, and India to propose a new detection method that is minimally destructive, in situ, and in real-time.

Bhattacharya said the techniques used to detect gravitational waves predicted by Einstein inspired the new method. The basic idea is to pass laser light through the rotating superfluid. The light that emerged would then pick up a modulation at the frequency of superfluid rotation. Detecting this frequency in the light beam using existing technology yielded knowledge of the superfluid motion. The challenge was to ensure the laser beam did not disturb the superflow, which the team accomplished by choosing a light wavelength different from any that would be absorbed by the atoms.

“Our proposed method is the first to ensure minimally destructive measurement and is a thousand times more sensitive than any available technique,” said Bhattacharya. “This is a very exciting development, as the combination of optics with atomic superflow promises entirely new possibilities for sensing and information processing.”

Bhattacharya and his colleagues also showed that the light beam could actively manipulate supercurrents. In particular, they showed that the light could create quantum entanglement between two currents flowing in the same gas. Such entanglement could be useful for storing and processing quantum information.

Bhattacharya’s theoretical team on the paper consisted of RIT postdoctoral researchers Pardeep Kumar and Tushar Biswas, and alumnus Kristian Feliz ’21 (physics). The international collaborators consisted of professors Rina Kanamoto from Meiji University, Ming-Shien Chang from the Academia Sinica, and Anand Jha from the Indian Institute of Technology. Bhattacharya’s work was supported by a CAREER Award from the National Science Foundation.

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Materials provided by Rochester Institute of Technology. Original written by Luke Auburn. Note: Content may be edited for style and length.

Following dozens of children over the course of five years, a Boston University researcher has taken the closest look yet at the link between how babies’ brains are structured in infancy and their ability to learn a language at a young age, and to what degree their environment plays a role in brain and language development.

The new research, described in a paper published in Developmental Cognitive Neuroscience, finds that the brain’s organizational pathways might set a foundation for a child’s language learning abilities within the first year of life. These pathways are known as white matter, and they act as the connectors between the billions of neurons — called gray matter — that comprise the brain tissue. This allows for the exchange of signals and for all of the different tasks and functions we need to perform, as well as all of the biological processes that sustain us.

“A helpful metaphor often used is: white matter pathways are the ‘highways,’ and gray matter areas are the ‘destinations’,” says BU neuroscientist and licensed speech pathologist Jennifer Zuk, who led the study. Zuk, a College of Health & Rehabilitation Sciences: Sargent College assistant professor of speech, language, and hearing sciences, says the more someone does a certain task, like learning a new language, the stronger and more refined the pathways become in the areas of the brain responsible for that task, allowing information to flow more efficiently through the white matter highways. Recent evidence suggests that white matter most rapidly develops within the first two years of life, according to Zuk.

In addition to white matter development, scientists have long known that the environment also plays an important role in shaping a person’s language abilities, Zuk says. But many uncertainties remain about whether nature or nurture is more dominant in determining the makeup of white matter and how well a baby learns to communicate.

In their study, Zuk says, she and her colleagues sought answers to several specific questions: from very early on, to what extent does predisposed brain structure play a role in development? Does the brain develop in tandem with language, and is the environment ultimately driving the progress of both? And to what extent does brain structure in early infancy set children up for success with language?

To investigate this, Zuk and Boston Children’s Hospital researcher and study senior author Nadine Gaab met with 40 families with babies to take images of the infants’ brains using magnetic resonance imaging (MRI) and gather first-of-its-kind data on white matter development. No small feat, considering the babies needed to be sound asleep to allow for crisp capture of their brain activity and structure using MRI.

“It was such a fun process, and also one that calls for a lot of patience and perseverance,” says Zuk, who had to master the challenge of getting 4-to-18-month-old babies comfortable enough to snooze through the MRI process — the loud sounds of an MRI could be very disruptive to a sleeping baby. “There are very few researchers in the world using this approach,” she says, “because the MRI itself involves a rather noisy background…and having infants in a naturally deep sleep is very helpful in accomplishing this pretty crazy feat.”

It’s also the first time that scientists have used MRI to look at the relationship between brain structure and language development in full-term, typically developing children from infancy to school age.

One important white matter pathway the researchers looked at using MRI is called the arcuate fasciculus, which connects two regions of the brain responsible for language production and comprehension. Using MRI, the researchers measured the organization of white matter by looking at how easily water diffuses through the tissue, indicating the pathway’s density.

Five years after first rocking babies to sleep and gently tucking them inside an MRI machine, Zuk and her collaborators met up with the children and their families again to assess each child’s emerging language abilities. Their assessments tested each one’s vocabulary knowledge, their ability to identify sounds within individual words, and their ability to blend individual sounds together to understand the word it makes.

According to their findings, children born with higher indications of white matter organization had better language skills five years later, suggesting that communication skills could be strongly linked to predisposed brain structure. But, Zuk says, this is only the first piece of a very complicated puzzle.

“Perhaps the individual differences in white matter we observed in infancy might be shaped by some combination of a child’s genetics and their environment,” she says. “But it is intriguing to think about what specific factors might set children up with more effective white matter organization early on.”

Although their findings indicate a foundation for language is established in infancy, “ongoing experience and exposure [to language] then builds upon this foundation to support a child’s ultimate outcomes,” Zuk says.

She says this means that during the first year of a child’s life “there’s a real opportunity for more environmental exposure [to language] and to set children up for success in the long term.”

Zuk and her research partners plan to continue investigating the relationship between environmental and genetic components of language learning. Their goal is to help parents and caretakers identify early risk factors in language development in young children and determine strategies for strengthening babies’ communicative skills early on in life.

3D printing, also known as additive manufacturing, is more versatile and efficient than casting. It adds a material with precision, often in complex geometries, with considerably less excess to cut away. Adding low-dimensional nanomaterials such as CNTs, graphene, metal nanoparticles and quantum dots allows 3D-printed materials to adapt to external stimuli, giving them features such as electrical and thermal conductance, magnetism and electrochemical storage.

But 3D printing using plastic, metal or something else entirely isn’t new. What Tech researchers have done differently is use polymer nanocomposites (made of epoxy, carbon nanotubes and nano-clay) and a printing process that doesn’t sacrifice functionality. The junction of material type and morphology — size, shape, structure — in polymer nanocomposite inks is the ultimate in form meeting function.

The exploration of process, morphology and properties of polymeric inks is the subject of an article recently published in the journal Additive Manufacturing by Parisa Pour Shahid Saeed Abadi, an engineer who explores the interface of materials, mechanics and medicine, and graduate student Masoud Kasraie.

Abadi and Kasraie point out that before researchers can sprint off to the races using polymeric inks, they must first learn to walk. The first step is digging into the intersection of the macro scale (how our eyes see a material performing) and the nano scale (what we can’t see, but know is occurring).

Building Understanding Before Market Share

While polymer nanocomposites and 3D-printing products and services both have billion-dollar market values, nanomaterial 3D printing only has a market value of approximately $43 million, Abadi noted.

“For national prosperity and sustaining global leadership in manufacturing, the gap between the real-world applications of 3D printing and nanomaterials versus nanomaterial 3D printing needs to be closed,” Abadi said. “The gap exists due to lack of control of nanocomposite properties in the 3D-printing process, because we don’t fully understand the process-morphology-property relationship.”

The bottleneck is understanding the complex interplay between the macro-scale mechanics of 3D-printing processes and the nano-scale mechanics and physics of nanocomposites. Abadi and Kasraie’s research seeks to loosen the bottleneck by exploring the relationship between 3D-printing process parameters and nanomaterial morphology in nanocomposite printing inks, which is the most important but least explored piece of the puzzle.

The Many Benefits of Nanomaterial Ink

Moving beyond the science of nanocomposite ink, the material holds great promise because of its many functionalities. One advantage of 3D printing is near-complete control over the final product’s shape.

The conductivity of Abadi and Kasraie’s nanomaterial ink is an exceptionally handy trait that gives the printed epoxy the potential to double as electrical wiring — whether in a circuit board, an airplane’s wing or in 3D-printed actuators for guiding catheters in blood vessels. Another useful trait of the nanocomposite polymer ink is its strength.

“In comparison with steel and aluminum, we see 80% weight reduction with epoxy composite with same strength,” Kasraie said.

Finally, in the medical field and aerospace and electronics industries, where defects and damage can spell big trouble, the nanocomposites serve a safety function.

“When something breaks, a tiny crack starts from a microscale defect and progresses until it breaks the entire structure,” Abadi said. “Nanocomposite features make bridges in those cracks and don’t let the cracks grow. This is one of the mechanisms through which carbon nanotubes increase the mechanical strength of the material.”

Property-to-weight ratio, electrical conductivity, increased strength and ease of application are just a few of the many promising reasons why polymer nanocomposite inks will likely replace traditional epoxies.