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WEST LAFAYETTE, Ind. – Surgeons may soon be able to localize critical regions in tissues and organs during a surgical operation thanks to a new, patent-pending Purdue University biosensor that can be printed in 3D using an automated printing system.

Chi Hwan Lee created the biosensor, which allows for simultaneous recording and imaging of tissues and organs during a surgical operation. Lee is the Leslie A. Geddes Assistant Professor of Biomedical Engineering in the Weldon School of Biomedical Engineering and assistant professor of mechanical engineering. Lee also has a courtesy appointment in materials engineering.

"Simultaneous recording and imaging could be useful during heart surgery in localizing critical regions and guiding surgical interventions such as a procedure for restoring normal heart rhythms," Lee said.

Traditional methods to simultaneously record and image tissues and organs have proven difficult because other sensors used for recording typically interrupt the imaging process.

"To this end, we have developed an ultra-soft, thin and stretchable biosensor that is capable of seamlessly interfacing with the curvilinear surface of organs; for example the heart, even under large mechanical deformations, for example cardiac cycles," Lee said. "This unique feature enables the simultaneous recording and imaging, which allows us to accurately indicate the origin of disease conditions: in this example, real-time observations on the propagation of myocardial infarction in 3D."

By using soft bio-inks during the rapid prototyping of a custom-fit design, biosensors fit a variety of sizes and shapes of an organ. The bio-inks are softer than tissue, stretch without experiencing sensor degradation and have reliable natural adhesion to the wet surface of organs without needing additional adhesives. Kwan-Soo Lee's research group in Los Alamos National Laboratory is responsible for the formulation and synthesis of the bio-inks.

A number of prototype biosensors using different shapes, sizes and configurations have been produced. Craig Goergen, the Leslie A. Geddes Associate Professor of Biomedical Engineering in Purdue's Weldon School of Biomedical Engineering, and his laboratory group have tested the prototypes in mice and pigs in vivo.

"Professor Goergen and his team were successfully able to identify the exact location of myocardial infarctions over time using the prototype biosensors," Lee said. "In addition to these tests, they also evaluated the biocompatibility and anti-biofouling properties of the biosensors, as well as the effects of the biosensors on cardiac function. They have shown no significant adverse effects."

Understanding cellular metabolism - how a cell uses energy- could be key to treating a wide array of diseases, including vascular diseases and cancer.

While many techniques can measure these processes among tens of thousands of cells, researchers have been unable to measure them at the single-cell level.

Researchers at the University of Chicago's Pritzker School of Molecular Engineering and Biological Sciences Division have developed a combined imaging and machine learning technique that can, for the first time, measure a metabolic process at both the cellular and sub-cellular levels.

Using a genetically encoded biosensor paired with artificial intelligence, the researchers were able to measure glycolysis, the process of turning glucose into energy, of single endothelial cells, the cells that line blood vessels.

They found that when these cells move and contract, they use more glucose, and they also found that cells uptake glucose through a previously unknown receptor. Understanding this process could lead to better treatments for cancer and vascular diseases, including COVID-19.

The research, published in Nature Metabolism, was led by Assoc. Prof. Yun Fang and co-led by Asst. Prof. Jun Huang, with former postdoctoral fellow and now Asst. Prof David Wu and biophysical sciences graduate student Devin Harrison.

"Understanding cellular metabolism is universally important," Huang said. "By measuring single-cell metabolism, we potentially have a new way of treating a wide range of diseases."

"This is the first time that we can visualize cellular metabolism at different temporal and spatial scales, even at the subcellular level, which could fundamentally change the language and approach for researchers to study cellular metabolism," Fang said.

Measuring glycolysis

Endothelial cells normally provide a tight layer inside blood vessels, but they can contract, leaving gaps within this layer, when they need help from the immune system. Abnormal contraction can cause leaky blood vessels, leading to heart attack or stroke. Such contraction in blood vessels around the lungs can also cause fluid to leak in, which happens in the case of acute respiratory distress syndrome. (This often occurs in patients with severe cases of COVID-19.)

To better understand how cells metabolize energy to fuel this contraction, the researchers turned to Förster resonance energy transfer sensors--genetically encoded biosensors that can measure the amount of lactate inside cells. Lactate is the byproduct of glycolysis.

Though the researchers did not create the sensors, by pairing the sensors with machine learning algorithms, they created an even more powerful technique that allowed them to image cells, analyze the data, and parse out glycolysis reactions at the cellular and subcellular levels.

"Now we can look at and understand details within the cells, like certain areas of cells where there is an increase of glycolysis," Fang said. "This is a key technological innovation."

They were able to measure just how much glucose cells used when they contracted and moved, and they also found a new mechanism of glucose transport mediated by the cell's cytoskeleton - a receptor called GLUT3 - that these cells use to uptake glucose.

Creating new treatments

Understanding how glycolysis works at the cellular level could ultimately lead to treatments that inhibit this process when beneficial - in the case of leaky blood vessels in patients with atherosclerosis, for example. It could also help patients whose immune systems are overreacting to COVID-19, for example, and need help closing the gaps within their endothelial cells around their lungs.

"If we can find a way to inhibit contraction, we could lessen the acute respiratory distress syndrome in COVID-19 patients," Fang said.

It also has important implications in treating cancer. Endothelial migration and proliferation, driven by glycolysis, are major cellular processes involved in vascular growth, which is necessary for tumor survival and growth. Understanding just how this works could help researchers both destroy tumors and inhibit tumor growth.

It could also be useful in CAR T-cell therapy, which recruits the body's own immune system to fight tumors. While the therapy has been lifesaving for some, many patients don't respond to it. Since endothelial cells are important for allowing T-cells to infiltrate tumors and cellular metabolism is instrumental to T-cell functions, researchers believe that modulating cellular metabolism could help create a better immunotherapy system.

The researchers are currently testing such inhibitors to treat COVID-19-induced acute respiratory distress syndrome at Argonne National Laboratory.

"Can we ultimately reprogram cells through metabolism?" Huang said. "It's an important question, and we need to understand just how metabolism works. There is huge potential here, and this is just the starting point."

Research shows that inhibiting necroptosis, a form of cell death, could be a novel therapeutic approach for treating chronic obstructive pulmonary disease (COPD), an inflammatory lung condition, also known as emphysema, that makes it difficult to breathe.

Published in the prestigious American Journal of Respiratory and Critical Care Medicine, the study by a team of Australian and Belgian researchers, revealed elevated levels of necroptosis in patients with COPD.

By inhibiting necroptosis activity, both in the lung tissue of COPD patients as well as in specialised COPD mouse models, the researchers found a significant reduction in chronic airway inflammation as well as damage to the lung.

Professor Phil Hansbro, Director of the Centenary UTS Centre for Inflammation who led the research team, said that necroptosis was a form of cell death known to drive tissue inflammation and destruction.

"Necroptosis, apoptosis and necrosis are all forms of cell death but they operate in distinctly different ways. Significantly, in necroptosis, a cell bursts, dispersing its contents into nearby tissues resulting in an immune and inflammation response."

"Our research suggests that inhibiting necroptosis and preventing this inflammation response may be a new therapeutic approach to treating COPD," said Professor Hansbro.

Joint first author on the study, Dr Zhe Lu, a researcher at the University of Newcastle, said that their study was the first of its type to be able to distinguish between the roles of necroptosis and apoptosis in COPD.

"Necroptosis is generally pro-inflammatory. Apoptosis, however, tends to be non-inflammatory as it's a more ordered form of cell death-a cell self-degrades as opposed to bursting and there's no leakage of cell contents. This may explain why, in our study, it's the inhibition of necroptosis and not apoptosis that reduces lung damage and COPD associated inflammation," said Dr Lu.

A debilitating respiratory condition and a leading cause of death worldwide, there are currently no treatments that halt or reverse the progression of COPD.

"Our research suggests that it is the type of cell death associated with COPD that is important and that the development of new drugs that can interfere or intervene in the necroptosis process could be a new targeted therapy for this common lung disease," said Professor Hansbro.

The study was led by researchers from the Centenary Institute, University of Technology Sydney, University of Newcastle and Ghent University Hospital, Belgium.

Necroptosis Signalling Promotes Inflammation, Airway Remodelling and Emphysema in COPD is published in the American Journal of Respiratory and Critical Care Medicine.

Electrons are ubiquitous among atoms, subatomic tokens of energy that can independently change how a system behaves--but they also can change each other. An international research collaboration found that collectively measuring electrons revealed unique and unanticipated findings. The researchers published their results on May 17 in Physical Review Letters.

"It is not feasible to obtain the solution just by tracing the behavior of each individual electron," said paper author Myung Joon Han, professor of physics at KAIST. "Instead, one should describe or track all the entangled electrons at once. This requires a clever way of treating this entanglement."

Professor Han and the researchers used a recently developed "many-particle" theory to account for the entangled nature of electrons in solids, which approximates how electrons locally interact with one another to predict their global activity.

Through this approach, the researchers examined systems with two orbitals -- the space in which electrons can inhabit. They found that the electrons locked into parallel arrangements within atom sites in solids. This phenomenon, known as Hund's coupling, results in a Hund's metal. This metallic phase, which can give rise to such properties as superconductivity, was thought only to exist in three-orbital systems.

"Our finding overturns a conventional viewpoint that at least three orbitals are needed for Hund's metallicity to emerge," Professor Han said, noting that two-orbital systems have not been a focus of attention for many physicists. "In addition to this finding of a Hund's metal, we identified various metallic regimes that can naturally occur in generic, correlated electron materials."

The researchers found four different correlated metals. One stems from the proximity to a Mott insulator, a state of a solid material that should be conductive but actually prevents conduction due to how the electrons interact. The other three metals form as electrons align their magnetic moments -- or phases of producing a magnetic field -- at various distances from the Mott insulator. Beyond identifying the metal phases, the researchers also suggested classification criteria to define each metal phase in other systems.

"This research will help scientists better characterize and understand the deeper nature of so-called 'strongly correlated materials,' in which the standard theory of solids breaks down due to the presence of strong Coulomb interactions between electrons," Professor Han said, referring to the force with which the electrons attract or repel each other. These interactions are not typically present in solid materials but appear in materials with metallic phases.

The revelation of metals in two-orbital systems and the ability to determine whole system electron behavior could lead to even more discoveries, according to Professor Han.

"This will ultimately enable us to manipulate and control a variety of electron correlation phenomena," Professor Han said.

When animals are hot, they eat less. This potentially fatal phenomenon has been largely overlooked in wild animals, explain researchers from The Australian National University (ANU).

According to lead author Dr Kara Youngentob, it means climate change could be contributing to more deaths among Australia's iconic marsupials, like the greater glider, than previously thought.

"Hot weather puts all animals off their food. Humans can deal with it fairly well; we usually have plenty of fat reserves and lots of different food options," Dr Youngentob said.

"But it's much more serious for animals with highly specialised diets, like greater gliders. If they don't eat regularly, they don't meet their nutritional requirements to stay alive. They also get most of their water from their food, so not eating leads to dehydration too.

"Even night-time temperatures can get hot enough to cause nocturnal animals to lose their appetite during heatwaves.

"A lot of the focus until now has been on the impact of climate change on food quality and quantity, but the bigger picture here is that hot animals eat less even if they have plenty of food."

We already have evidence that marsupials have trouble processing the natural toxins in eucalyptus leaves at high temperatures. But in this scenario, hot temperatures alone, even with a toxin free diet, can stop them from eating enough to stay alive.

Dr Youngentob said there are a few things we can do to address the issue, including protecting sources of food.

"If you're eating less, the small amount you do eat needs to be more nutritious. Not all eucalypts have the same level of nutrients, so we need to identify and protect those areas of the forest that have the best quality food for these animals," Dr Youngentob said.

"We should restore degraded forest with more nutritious food trees too.

"We also need to look closely at what makes some forests cooler, and what contributes to forests getting hotter so we can protect and expand those cooler microclimates."

Parenting is one of life's greatest joys, right? Not for everyone. New research from Michigan State University psychologists examines characteristics and satisfaction of adults who don't want children.

As more people acknowledge they simply don't want to have kids, Jennifer Watling Neal and Zachary Neal, both associate professors in MSU's department of psychology, are among the first to dive deeper into how these "child-free" individuals differ from others.

"Most studies haven't asked the questions necessary to distinguish 'child-free' individuals -- those who choose not to have children -- from other types of nonparents," Jennifer Watling Neal said. "Nonparents can also include the 'not-yet-parents' who are planning to have kids, and 'childless' people who couldn't have kids due to infertility or circumstance. Previous studies simply lumped all nonparents into a single category to compare them to parents."

The study -- published June 16 in PLOS ONE -- used a set of three questions to identify child-free individuals separately from parents and other types of nonparents. The researchers used data from a representative sample of 1,000 adults who completed MSU's State of the State Survey, conducted by the university's Institute for Public Policy and Social Research.

"After controlling for demographic characteristics, we found no differences in life satisfaction and limited differences in personality traits between child-free individuals and parents, not-yet-parents, or childless individuals," Zachary Neal said. "We also found that child-free individuals were more liberal than parents, and that people who aren't child-free felt substantially less warm toward child-free individuals."

Beyond findings related to life satisfaction and personality traits, the research unveiled additional unexpected findings.

"We were most surprised by how many child-free people there are," Jennifer Watling Neal said. "We found that more than one in four people in Michigan identified as child-free, which is much higher than the estimated prevalence rate in previous studies that relied on fertility to identify child-free individuals. These previous studies placed the rate at only 2% to 9%. We think our improved measurement may have been able to better capture individuals who identify as child-free."

Given the large number of child-free adults in Michigan, more attention needs to be paid to this group, the researchers said. For example, the researchers explained that their study only included one time point, so didn't examine when people decided to be child-free -- however, they hope forthcoming research will help the public understand both when people start identifying as child-free as well as the factors that lead to this choice.

Postdoctoral Researcher Outi Keinänen from the University of Helsinki developed a method to radiolabel plastic particles in order to observe their biodistribution on the basis of radioactivity with the help of positron emission tomography (PET). As a radiochemist, Keinänen has in her previous radiopharmaceutical studies utilised PET imaging combined with computed tomography (CT), which produces a very accurate image of the anatomical location of the radioactivity signal.

In the recently completed study, radiolabelled plastic particles were fed to mice, and their elimination from the body was followed with PET-CT scans. This was the first time that the movement and location of plastic particles in a living mammalian system were observed in real time.

The study utilised polystyrene particles of four different sizes: 20 nm, 220 nm, 1 μm and 6 μm. The journey of the radiolabelled plastic particles through the gastrointestinal tract was followed for two days (48 hours) through PET-CT scans.

The study, which was recently published in Scientific Reports journal, demonstrated that most of the particles had been eliminated from the mice naturally, through faeces within two days. Not much translocation of plastic particles from the gastrointestinal tract to elsewhere in the body was seen, and the smallest particles were eliminated from the body at a faster rate than the larger ones.

In addition to PET imaging, the findings were verified by thoroughly measuring the radioactivity of the tissues and organs of the mice. The persistence of the radiolabel on the surface of the plastic particles was verified by collecting murine gastrointestinal tracts at several different time points after administering the particles. The gastrointestinal tracts of mice that were put down at different timepoints were cut open, ground and separated into several fractions based on size. The share of the non-attached radiolabel was very small compared to the radiolabel still attached to the plastic particles. This was proof that the monitored radiation signal described the passage of the plastic particles well.

First and foremost, the study surveyed the usefulness of PET imaging in the study of micro- and nanoplastics, demonstrating that PET imaging enables accurate and non-invasive observation of plastic particles in living animals. Consequently, PET imaging may well become an important element of investigations into the health effects of plastics on mammals.

"While only a single small dose of polystyrene particles was fed to the mice, people are exposed daily to a range of micro- and nanoplastics. Therefore, we cannot draw direct conclusions on the accumulation of plastics in mammals and their effects on the basis of this study alone," Keinänen notes.

"In addition to ingesting plastics, the air we breathe contains small particles of plastic. Further studies are in fact in the pipeline," Keinänen promises.

Next up, the researchers wish to investigate the long-term consequences of daily exposure to micro- and nanoplastics, as well as the accumulation of inhaled plastic particles in mice. In future projects, the aim is to use different plastic materials in addition to polystyrene, the type of plastic used in this study.

These findings were published in the journal Cellular and Molecular Life Sciences on 8 June 2021.

Huge splicing diversity in the brain

The human genome was sequenced around 20 years ago. Since then, the sequence information encoding our proteins is known - at least in principle. However, this information is not continuously stored in the individual genes, but is divided into smaller coding sections. These coding sections, also known as exons, are assembled in a process called splicing. Depending on the gene, different exon combinations are possible, which is why they are referred to as different or alternative splicing combinations.

Almost all 20,000 human genes can be alternatively spliced. A particularly huge variety of different splice variants is found in the brain, which allows for creating a huge diversity and allows to adapt the proteins to specific requirements. "However, it is not easy to determine, which protein variants are actually present," says Andreas Reiner. "Sequencing of already-spliced messenger RNAs (mRNAs), so-called RNA-Seq data, which are now increasingly being obtained with high-throughput approaches, offers a way out." Robin Herbrechter and Andreas Reiner now used such data to obtain an overview of all ionotropic glutamate receptor splice variants.

New glutamate receptor variants detected

Using bioinformatic methods, the researchers aligned billions of mRNA sequence snippets to the genome to reconstruct the frequency of individual splice events. This method also enabled them to detect new, previously unknown splice variants. There were quite a few surprises: the systematic analysis showed that some variants found in the previously studied model organisms mouse and rat do not occur in humans at all, or are much less abundant than previously assumed.

"Among the newly identified isoforms, some are particularly exciting, as they are quite different from the previously known variants and could thus have new functions," says Robin Herbrechter. This includes a protein domain formed by the gene of the GluA4 AMPA receptor, as well as the first description of a delta receptor 1 (GluD1) isoform. While the focus will now be on analysing these variants, also further bioinformatic analyses are planned, for example to determine which cell types produce the different splice variants.

In the majority of insects, metamorphosis fosters completely different looking larval and adult stages. For example, adult butterflies are completely different from their larval counterparts, termed caterpillars. This "decoupling" of life stages is thought to allow for adaptation to different environments. Researchers of the University of Bonn now falsified this text book knowledge of evolutionary theory for stoneflies. They found that the ecology of the larvae largely determines the morphology of the adults by investigating 219 earwig and stonefly species at high-resolution particle accelerators. The study has now been published in the journal Proceedings of the Royal Society B.

The stonefly species Perla marginata leads a "double life": It spends its early years as a larva in European streams. It has gills and hides under stones in flowing waters to prey on other insect larvae. "This stage is mainly spent with taking up energy and growing," says PhD student Peter Rühr from the Institute of Evolutionary Biology and Ecology at the University of Bonn. After several molts, they finally metamorphose into adult specimens that live exclusively on land. They spend most of their time on the shore and fly around in a curiously lumbering fashion to find mates. They still have mouthparts, but during their adult life, which lasts only about two weeks, they hardly consume any food. "They live mainly from the resources acquired in their larval stage," adds Rühr.

Different life stages allow morphological adaptations

What is the importance of metamorphosis in the development of stonefly species and in general? To what extent are the different life stages connected? "These questions are for instance well studied in butterflies," says evolutionary biologist Prof. Dr. Alexander Blanke of the University of Bonn. "Previous results told us that metamorphosis allows for a "decoupling" of life stages so that each stage can adapt well to different environments. In extreme cases, this might even lead to a decoupling of food uptake and reproduction phases." For stoneflies, this means that they primarily feed as a larva and reproduce only on land during the adult stage.

But, although the different life stages seem to be decoupled, this is not the case for all animal groups that undergo metamorphosis. The zoologists at the University of Bonn studied an extensive set of stonefly species and also included the closely related earwigs for comparison. "We chose these two groups because although they are closely related, they show very different ways of life," Blanke explains. Unlike stoneflies, earwigs live exclusively on land and go through many mini-stages shedding their skin several times.

Using particle accelerators at the Karlsruhe Institute of Technology, the German Electron Synchrotron in Hamburg, and the Paul Scherrer Institute in Villigen, Switzerland, the researchers scanned 219 earwig and stonefly species in order to analyze whether adult morphology is correlated with larval behaviour. The synchrotron radiation was the preferred method because it allows extremely fast scans with very high resolution. For the analysis, the researchers converted the image stacks into high-resolution three-dimensional digital models.

Comparison with almost 1000 scientific publications

The researchers then characterized the shape of the heads and compared them to data on feeding behavior and habitat use from nearly 1,000 scientific publications. They found that the change from the larval to the adult stage in stoneflies is not accompanied by a pronounced decoupling of the two stages. "The head shape of the adult stoneflies is largely influenced by the larvae," Rühr summarizes. "The ecology of the young therefore determines the appearance of the adult animals."

This refines a common thesis in evolutionary research that metamorphosis allows for a decoupling of life stages. "This is still valid for butterflies, but it is not for stoneflies," Blanke says. "A more graded view on the strength of metamorphosis would be strongly advisable." Morphological adaptations during different life stages also occur if metamorphosis is much weaker than in butterflies. Blanke: "For the first time this study sheds light on how strongly successive life stages are coupled in insects without a pupal stage."

In a new publication from Cardiovascular Innovations and Applications; DOI https://doi.org/10.15212/CVIA.2021.0011, Xiao-lei Yin, Dong-xue Liang, Lu Wang, Jing Qiu, Zhi-yun Yang, Jian-zeng Dong and Zhao-yuan Ma from Tsinghua University, Beijing, China; Capital Medical University, Beijing, China and The First Affiliated Hospital of Zhengzhou University, Zhengzhou, China analyse coronary angiography video interpolation methods to reduce x-ray exposure frequency based on deep learning.

Cardiac coronary angiography is a major technique that assists physicians during interventional heart surgery. Under X-ray irradiation, the physician injects a contrast agent through a catheter and determines the coronary arteries' state in real time. However, to obtain a more accurate state of the coronary arteries, physicians need to increase the frequency and intensity of X-ray exposure, which will inevitably increase the potential for harm to both the patient and the surgeon. In the work reported here, the authors use advanced deep learning algorithms to find a method of frame interpolation for coronary angiography videos that reduces the frequency of X-ray exposure by reducing the frame rate of the coronary angiography video, thereby reducing X-ray-induced damage to physicians.

The authors established a new coronary angiography image group dataset containing 95,039 groups of images extracted from 31 videos. Each group includes three consecutive images, which are used to train the video interpolation network model and applied six popular frame interpolation methods to the dataset to confirm that the video frame interpolation technology can reduce the video frame rate and reduce exposure of physicians to X-rays.

Commonplace pharmaceuticals, such as ibuprofen, can carry with them an inherent flaw in their atomic structure, which pairs the active, beneficial ingredient with a potentially ineffective -- or even toxic -- counterpart. New research could hold the key to more easily isolating the good while removing the unwanted.

Dr. Shoufeng Lan, assistant professor in the J. Mike Walker '66 Department of Mechanical Engineering at Texas A&M University, is leading a team investigating the use of electromagnetic control over the synthesis of chiral compounds at an atomic level -- a process that could lead to a plethora of practical applications, including in the pharmaceutical industry. The team's research was recently published in the journal Nature Communications.

"Mysteriously, all living organisms on the Earth consist of only left-handed amino acids and right-handed sugars, but not their mirrored counterparts," Lan said. "The phenomenon is the so-called homochirality of life and it is the ultimate form of asymmetric synthesis."

Lan used the example of a human hand to demonstrate the concept of chirality, noting that if you were to create a mirror image of your hand, it could not be perfectly superimposed over the original.

By identifying a successful method of using asymmetrical synthesis to create new versions of structures for items like ibuprofen, Lan said better versions of generic pharmaceuticals with reduced toxicity could be created at a lower cost than currently available due to the current purification process.

However, to achieve success, the researchers will first need to overcome the practical need to implement this magnetic effect on asymmetric synthesis at room temperature. Currently, this effect is relatively weak, even with a strong magnetic field or at a low temperature or -- 450 degrees.

Lan said the topic of addressing chirality was the basis of the 2001 Nobel Prize in chemistry, which uses an existing chiral object -- a catalyst molecule -- to transfer chirality to the desired mirror image form as the final product.

"This Nature Communications paper demonstrated a giant atomic-scale magneto-chiral effect that is orders of magnitude stronger," Lan said. "By applying this effect, it is arguably possible to master an asymmetric synthesis or asymmetric self-assembling."

Lan said his team's research could prove revolutionary to the field by creating a new iteration of biomedical, chemical and pharmaceutical applications. For example, by asymmetrically synthesizing only the active component of racemic Lexapro -- the most common medication in the United States with more than 25 million prescriptions -- the research might reduce the drug's side effects.

'We anticipate that our demonstration could lead to the creation of chiral seeds at the atomic scale," Lan said. "Upon them, we hope to transfer the chirality using cutting-edge technologies, such as a metal-organic framework, to create chiral materials from nanoscales to macroscales."

RUDN University biologist studied the aggressive impact of environmental factors (water, salts, and ozone) on ultrathin nanofibers of biopolymers. The results will help choosing suitable bioplastic depending on the use; for example, for medical implants, biodegradable packaging or filters for water cleaning. The results are published in the journal Polymers.

Bioplastics are an alternative to ordinary plastics. They are obtained from waste of plant and food industry. The safe composition allows using them as filters for gases and liquids, as "sponges" for cleaning reservoirs and medical implants. Depending on the field of use, bioplastics are exposed to different environmental factors -- light, water, temperature, and the physiological environment. It is still not known how the external environment affects the nanostructure of bioplastics products. The RUDN University biologist found out how the environment affects the nanofibers of two plastics of organic origin: polylactide and polyhydroxybutyrate.

"We obtained the electrospun ultrathin fibers based on thermoelastic biopolyesters. Both of them produced from the naturally abundant renewable resources, namely, polylactide and polyhydroxybutyrate. But our main aim was not to obtain the fibers themselves, but to determine whether their properties are preserved under the impact of aggressive environmental factors", Alexandre Vetcher, PhD, Deputy Director of the Scientific-educational centre "Nanotechnologies" of RUDN University

Biologists obtained six types of fibers from polyhydroxybutyrate powder and polylactide granules by electrospinning method. The polymer solution was placed in a high-voltage electrostatic field, which "pulled" the solution into thin jets. After cooling, they turned into fibers. Six types of finished fibers differed in the content of polymers in the composition-pure polylactide and polyhydroxybutyrate and their blends in different ratios.

RUDN University biologists have studied the impact of water, physiological environment (internal environment of the body) and ozone on the resulting nanofibers. It turned out that the water vapor absorption depends on the polymer structure. The higher the proportion of polylactide, the more water the fibres absorb: up to 1% of the sample weight. Scientists used a phosphate buffer to simulate the internal environment of a living organism. Polylactide fibers lost more than 50% of their mass in solution over 21 days, and samples with a high polyhydroxybutyrate content lost less than 15%. Also, polymers with a high content of polylactide absorbed ozone molecules more quickly when treated with a stream of this gas and as a result of such intense oxidation they were destroyed. Ozone penetrated the fibers with a 50:50 ratio of the two polymers the fastest.

"We demonstrated that biodegradable nanofibers, which are characterized by a crystalline structure, are more resistant to decomposition by water and ozone. Now it is necessary to test these materials for resistance to UV light and microorganisms in order to determine the optimal applications for each type of fiber", Alexandre Vetcher, PhD, Deputy Director of the Scientific-educational centre "Nanotechnologies" of RUDN University.

Bay Area scientists have captured the real-time electrical activity of a beating heart, using a sheet of graphene to record an optical image -- almost like a video camera -- of the faint electric fields generated by the rhythmic firing of the heart's muscle cells.

The graphene camera represents a new type of sensor useful for studying cells and tissues that generate electrical voltages, including groups of neurons or cardiac muscle cells. To date, electrodes or chemical dyes have been used to measure electrical firing in these cells. But electrodes and dyes measure the voltage at one point only; a graphene sheet measures the voltage continuously over all the tissue it touches.

The development, published online last week in the journal Nano Letters, comes from a collaboration between two teams of quantum physicists at the University of California, Berkeley, and physical chemists at Stanford University.

"Because we are imaging all cells simultaneously onto a camera, we don't have to scan, and we don't have just a point measurement. We can image the entire network of cells at the same time," said Halleh Balch, one of three first authors of the paper and a recent Ph.D. recipient in UC Berkeley's Department of Physics.

While the graphene sensor works without having to label cells with dyes or tracers, it can easily be combined with standard microscopy to image fluorescently labeled nerve or muscle tissue while simultaneously recording the electrical signals the cells use to communicate.

"The ease with which you can image an entire region of a sample could be especially useful in the study of neural networks that have all sorts of cell types involved," said another first author of the study, Allister McGuire, who recently received a Ph.D. from Stanford and. "If you have a fluorescently labeled cell system, you might only be targeting a certain type of neuron. Our system would allow you to capture electrical activity in all neurons and their support cells with very high integrity, which could really impact the way that people do these network level studies."

Graphene is a one-atom thick sheet of carbon atoms arranged in a two-dimensional hexagonal pattern reminiscent of honeycomb. The 2D structure has captured the interest of physicists for several decades because of its unique electrical properties and robustness and its interesting optical and optoelectronic properties.

"This is maybe the first example where you can use an optical readout of 2D materials to measure biological electrical fields," said senior author Feng Wang, UC Berkeley professor of physics. "People have used 2D materials to do some sensing with pure electrical readout before, but this is unique in that it works with microscopy so that you can do parallel detection."

The team calls the tool a critically coupled waveguide-amplified graphene electric field sensor, or CAGE sensor.

"This study is just a preliminary one; we want to showcase to biologists that there is such a tool you can use, and you can do great imaging. It has fast time resolution and great electric field sensitivity," said the third first author, Jason Horng, a UC Berkeley Ph.D. recipient who is now a postdoctoral fellow at the National Institute of Standards and Technology. "Right now, it is just a prototype, but in the future, I think we can improve the device."

Graphene is sensitive to electric fields

Ten years ago, Wang discovered that an electric field affects how graphene reflects or absorbs light. Balch and Horng exploited this discovery in designing the graphene camera. They obtained a sheet of graphene about 1 centimeter on a side produced by chemical vapor deposition in the lab of UC Berkeley physics professor Michael Crommie and placed on it a live heart from a chicken embryo, freshly extracted from a fertilized egg. These experiments were performed in the Stanford lab of Bianxiao Cui, who develops nanoscale tools to study electrical signaling in neurons and cardiac cells.

The team showed that when the graphene was tuned properly, the electrical signals that flowed along the surface of the heart during a beat were sufficient to change the reflectance of the graphene sheet.

"When cells contract, they fire action potentials that generate a small electric field outside of the cell," Balch said. "The absorption of graphene right under that cell is modified, so we will see a change in the amount of light that comes back from that position on the large area of graphene."

In initial studies, however, Horng found that the change in reflectance was too small to detect easily. An electric field reduces the reflectance of graphene by at most 2%; the effect was much less from changes in the electric field when the heart muscle cells fired an action potential.

Together, Balch, Horng and Wang found a way to amplify this signal by adding a thin waveguide below graphene, forcing the reflected laser light to bounce internally about 100 times before escaping. This made the change in reflectance detectable by a normal optical video camera.

"One way of thinking about it is that the more times that light bounces off of graphene as it propagates through this little cavity, the more effects that light feels from graphene's response, and that allows us to obtain very, very high sensitivity to electric fields and voltages down to microvolts," Balch said.

The increased amplification necessarily lowers the resolution of the image, but at 10 microns, it is more than enough to study cardiac cells that are several tens of microns across, she said.

Another application, McGuire said, is to test the effect of drug candidates on heart muscle before these drugs go into clinical trials to see whether, for example, they induce an unwanted arrhythmia. To demonstrate this, he and his colleagues observed the beating chicken heart with CAGE and an optical microscope while infusing it with a drug, blebbistatin, that inhibits the muscle protein myosin. They observed the heart stop beating, but CAGE showed that the electrical signals were unaffected.

Because graphene sheets are mechanically tough, they could also be placed directly on the surface of the brain to get a continuous measure of electrical activity -- for example, to monitor neuron firing in the brains of those with epilepsy or to study fundamental brain activity. Today's electrode arrays measure activity at a few hundred points, not continuously over the brain surface.

"One of the things that is amazing to me about this project is that electric fields mediate chemical interactions, mediate biophysical interactions -- they mediate all sorts of processes in the natural world -- but we never measure them. We measure current, and we measure voltage," Balch said. "The ability to actually image electric fields gives you a look at a modality that you previously had little insight into."

A study of young immigrant mothers who are survivors of sex trafficking found that the trauma affected how they parented: it made them overprotective parents in a world perceived to be unsafe, it fueled emotional withdrawal when struggling with stress and mental health symptoms, and was a barrier to building confidence as mothers. Yet, they coped with such challenges finding meaning in the birth of their child and through social support and faith.

Results of the community-based participatory research study by researchers at Columbia University Mailman School of Public Health, Copenhagen University, and ECPAT-USA (End Child Prostitution and Trafficking-USA) appear in the journal PLOS One.

The researchers interviewed 14 young women (20-36 years) from Mexico and Central America who were survivors of sex trafficking to understand the effect of that experience on their relationship with their pre-school children. Recruited through the nonprofit Sanctuary for Families, participants had been forced to enter sex trafficking at an average age of 19 years, with one-third trafficked as minors. Most of these women experienced PTSD symptoms, despite having escaped their victimization 2 to 10 years earlier.

TRAUMA'S SCARS

The study found that many sex trafficking survivors questioned their ability to be "good mothers." This negative self-perception was linked to participants' experiences of disempowerment from being trafficked for sex. Most noted that their avoidant behaviors and generalized fear often led to overprotecting their young children and foregoing opportunities for socialization with other children or adults. When children are overprotected, their independence may be discouraged, hindering the development of autonomy and increasing the risk for developing anxiety and separation issues. Conversely, mothers also discussed how moments of sadness and emotional numbness lead them to feel emotionally disconnected from their children, decreasing their ability to respond to their young children's emotional needs in moments of stress.

Mothers' challenges to be emotionally present during stressful moments appeared to result from the accumulation of stressors before, during, and after victimization: neglect and abuse, forced separation from their older children, post-trafficking poverty, and migration-related stressors, rather than directly from the trafficking experiences. Fears of deportation and limited job options appeared to further contribute to their become stay-at-home mothers and engaging in overprotective parenting.

FINDING MEANING IN MOTHERHOOD

Despite these challenges, mothers found ways to cope--by finding meaning in the birth of their child and using social support and faith to build confidence. All participants regarded their children as the main reason for living, for working towards a better future. Many reported experiencing strong connections to their children, with moments of joy and playfulness. The study showed how the process of reestablishing feelings of happiness and trust through motherhood can help women find meaning in life, increasing their resilience and ability to cope with the consequences of traumatic experiences. Early childhood programs appeared to help mothers experience empowerment and develop stronger bonds with their children.

"We can support mothers' resiliency through government policies and programs aimed at reducing daily stressors and including mental health services, job and life skills training, and stable housing. These will facilitate women to be able to process their pain, while building confidence in their ability to be loving mothers," says first author Maria Martí Castañer, PhD, who carried out the research while a post-doctoral researcher at the Columbia Mailman School and is now at the Center for Migration, Ethnicity, and Health at the University of Copenhagen.

POLICY SOLUTIONS

The researchers propose several policies to support mothers who are survivors of sex trafficking. These include pre and postnatal mental health and psychosocial support, focusing on parenting-related changes; the provision of parenting and early childhood education programs to facilitate the development of healthier parent-child relationships; measures that improve living conditions and enhance long-term opportunities to regain independence and confidence to accelerate their recovery from trauma. The latter might include English language and literacy as well as job skills. These can help women re-construct their new identity in addition to supporting their role as mothers.

Anti-trafficking agencies, nonprofit organizations working with sex trafficking survivors, and healthcare providers involved in prenatal and child health care can play a key role in identifying women (and older adolescents) in need, and in encouraging their referral to programs that offering psychosocial, parenting, and early childhood support and education.

"Our project highlights the unique opportunities for partnership across legal and public health disciplines. Ultimately the wellbeing of these young migrant women and their children benefits from collaboration between legal and healthcare services. Such collaborations can help inform both disciplines and thus facilitate the provision of effective and more holistic care," senior author Manuela Orjuela-Grimm, MD, assistant professor of epidemiology and pediatrics says.

BACKGROUND ON SEX TRAFFICKING

According to estimates from the International Labor Organization, there are approximately 4.5 million victims of sexual exploitation at any given time, and 98 percent are estimated to be women or girls. An estimated that 15,000-50,000 people are trafficked annually in the U.S.

Central American women are trafficked en route to the U.S. with smugglers sometimes pass them on to traffickers. Others, especially women from Mexico, are seduced by young men who convince them with promises of a new life in new home towns only to place them in trafficking with threats of retaliation to their families.

Women from Mexico and Central America typically are sold for 15-minute sex acts between 15-20 times per day on a weekday and 25-35 times per day on the weekend. When women fail to meet their quota, their traffickers frequently beat, starve, and threaten them. Survivors of sex trafficking have high rates of comorbid mental health disorders and health problems.

Researchers from Skoltech and their colleagues from the UK have managed to create a stable giant vortex in interacting polariton condensates, addressing a known challenge in quantized fluid dynamics. The findings open possibilities in creating uniquely structured coherent light sources and exploring many-body physics under unique extreme conditions. The paper was published in the journal Nature Communications.

In fluid dynamics, a vortex is a region where a fluid revolves around a point (2D) or a line (3D); you've clearly seen one in your sink or may have felt one in the form of turbulence while flying. The quantum world also has vortices: the flow of a quantum fluid can create a zone where the particles revolve persistently around some point. The prototypical signature of such quantum vortices is their singular phase at the core of the vortex.

Skoltech Professors Natalia Berloff and Pavlos Lagoudakis and colleagues studied vortices created by polaritons - odd hybrid quantum particles that are half-light (photon) and half-matter (electrons) - forming a quantum fluid under the right conditions. They were looking for a way to create vortices in these polariton fluids with high values of angular momentum (i.e., getting them to rotate fast). These vortices, also known as giant vortices, are generally very hard to obtain as they tend to break apart into many smaller vortices with low angular momentum in other systems.

Creating stable giant vortices shows that non-equilibrium (open) quantum systems, like polariton condensates, can overcome some severe limits of their thermodynamic equilibrium counterpart such as Bose-Einstein condensates of cold atoms. Control over the vorticity of a quantum fluid could open new perspectives on analog simulation of gravity or black hole dynamics in the microscopic world. Moreover, the polariton condensate continuously emits photons that carry all the intricacies of the vortex which could become important for optical data storage, distribution, and processing applications.

The researchers had been working on using interacting polariton condensates as candidates to simulate a planar vector model known as the XY model. They realized that when multiple condensates were arranged into a regular polygon with an odd number of vertices the ground state of the whole system could correspond to a particle current along the polygon edge. By going from a triangle, pentagon, heptagon, and so on, the authors showed that the current rotated faster and faster, forming a giant vortex of varying angular momentum.

"The formation of stable clockwise, or anticlockwise, polariton currents along the perimeter of our polygons can be thought of as a result of geometric frustration between the condensates. The condensates interact like oscillators that want to be in antiphase with each other. But an odd-numbered polygon cannot satisfy this phase relation because of its rotational symmetry, and therefore the polaritons settle for the next-best thing which is a rotating current," first author Tamsin Cookson says.

"This is a very nice demonstration of how polaritons can provide a very flexible sandbox to probe some of the more complex phenomena of nature. What we show here is a system that shares a lot of characteristics with a black hole, which still emitting, a white hole if you wish!" Professor Lagoudakis adds.