Future VR Could Employ New Ultrahigh-res Display (Engineering)

By expanding on existing designs for electrodes of ultra-thin solar panels, Stanford researchers and collaborators in Korea have developed a new architecture for OLED – organic light-emitting diode – displays that could enable televisions, smartphones and virtual or augmented reality devices with resolutions of up to 10,000 pixels per inch (PPI). (For comparison, the resolutions of new smartphones are around 400 to 500 PPI.)

Illustration of the meta-OLED display and the underlying metaphotonic layer, which improves the overall brightness and color of the display while keeping it thin and energy efficient. ©Samsung Advanced Institute of Technology.

Such high-pixel-density displays will be able to provide stunning images with true-to-life detail – something that will be even more important for headset displays designed to sit just centimeters from our faces.

The advance is based on research by Stanford University materials scientist Mark Brongersma in collaboration with the Samsung Advanced Institute of Technology (SAIT). Brongersma was initially put on this research path because he wanted to create an ultra-thin solar panel design.

“We’ve taken advantage of the fact that, on the nanoscale, light can flow around objects like water,” said Brongersma, who is a professor of materials science and engineering and senior author of the Oct. 22 Science paper detailing this research. “The field of nanoscale photonics keeps bringing new surprises and now we’re starting to impact real technologies. Our designs worked really well for solar cells and now we have a chance to impact next generation displays.”

In addition to having a record-setting pixel density the new “metaphotonic” OLED displays would also be brighter and have better color accuracy than existing versions, and they’d be much easier and cost-effective to produce as well.

Hidden gems

At the heart of an OLED are organic, light-emitting materials. These are sandwiched between highly-reflective and semi-transparent electrodes that enable current injection into the device. When electricity flows through an OLED, the emitters give off red, green or blue light. Each pixel in an OLED display is composed of smaller sub-pixels that produce these primary colors. When the resolution is sufficiently high, the pixels are perceived as one color by the human eye. OLEDs are an attractive technology because they are thin, light and flexible and produce brighter and more colorful images than other kinds of displays.

This research aims to offer an alternative to the two types of OLED displays that are currently commercially available. One type – called a red-green-blue OLED – has individual sub-pixels that each contain only one color of emitter. These OLEDs are fabricated by spraying each layer of materials through a fine metal mesh to control the composition of each pixel. They can only be produced on a small scale, however, like what would be used for a smartphone.

Larger devices like TVs employ white OLED displays. Each of these sub-pixels contains a stack of all three emitters and then relies on filters to determine the final sub-pixel color, which is simpler to fabricate. Since the filters reduce the overall output of light, white OLED displays are more power-hungry and prone to having images burn into the screen.

OLED displays were on the mind of Won-Jae Joo, a SAIT scientist, when he visited Stanford from 2016 to 2018. During that time, Joo listened to a presentation by Stanford graduate student Majid Esfandyarpour about an ultrathin solar cell technology he was developing in Brongersma’s lab and realized it had applications beyond renewable energy.

“Professor Brongersma’s research themes were all very academically profound and were like hidden gems for me as an engineer and researcher at Samsung Electronics,” said Joo, who is lead author of the Science paper.

Joo approached Esfandyarpour after the presentation with his idea, which led to a collaboration between researchers at Stanford, SAI and Hanyang University in Korea.

“It was quite exciting to see that a problem that we have already thought about in a different context can have such an important impact on OLED displays,” said Esfandyarpour.

A fundamental foundation

The crucial innovation behind both the solar panel and the new OLED is a base layer of reflective metal with nanoscale (smaller than microscopic) corrugations, called an optical metasurface. The metasurface can manipulate the reflective properties of light and thereby allow the different colors to resonate in the pixels. These resonances are key to facilitating effective light extraction from the OLEDs.

“This is akin to the way musical instruments use acoustic resonances to produce beautiful and easily audible tones,” said Brongersma, who conducted this research as part of the Geballe Laboratory for Advanced Materials at Stanford.

For example, red emitters have a longer wavelength of light than blue emitters, which, in conventional RGB-OLEDs, translates to sub-pixels of different heights. In order to create a flat screen overall, the materials deposited above the emitters have to be laid down in unequal thicknesses. By contrast, in the proposed OLEDs, the base layer corrugations allow each pixel to be the same height and this facilitates a simpler process for large-scale as well as micro-scale fabrication.

In lab tests, the researchers successfully produced miniature proof-of-concept pixels. Compared with color-filtered white-OLEDs (which are used in OLED televisions) these pixels had a higher color purity and a twofold increase in luminescence efficiency – a measure of how bright the screen is compared to how much energy it uses. They also allow for an ultrahigh pixel density of 10,000 pixels-per-inch.

The next steps for integrating this work into a full-size display is being pursued by Samsung, and Brongersma eagerly awaits the results, hoping to be among the first people to see the meta-OLED display in action.

References: Won-Jae Joo, Jisoo Kyoung, Majid Esfandyarpour et al., “Metasurface-driven OLED displays beyond 10,000 pixels per inch”, Science, vol. 370, Issue 6515, pp. 459-463, 2020. DOI: 10.1126/science.abc8530 link: https://science.sciencemag.org/content/370/6515/459/tab-article-info

Provided by Stanford University

Tel Aviv University Researchers Discover Molecular Link Between Diet And Risk Of Cancer (Medicine / Oncology)

An international team of researchers has identified a direct molecular link between meat and dairy diets and the development of antibodies in the blood that increase the chances of developing cancer. This connection may explain the high incidence of cancer among those who consume large amounts of dairy products and red meat, similar to the link between high cholesterol and an increased risk of heart disease.

©Tel Aviv University

The study was led by Dr. Vered Padler-Karavani of the Department of Cell Research and Immunology at the Shmunis School of Biomedicine and Cancer Research at Tel Aviv University’s George S. Wise Faculty of Life Sciences. The results of the research were published on September 23, 2020, in BMC Medicine.

Neu5Gc is a sugar molecule found in the tissues of mammals but not in poultry or fish. Humans develop antibodies to Neu5Gc in infancy, when they are first exposed to dairy and meat products. While it is known that these antibodies increase the risk of cancer, especially colorectal cancer, no direct link had been found between the antibodies and meat and dairy consumption.

For the study, the researchers used samples from NutriNet-Santé, an extensive national nutritional survey conducted in France. Salam Bashir, a PhD student in Dr. Padler-Karavani’s lab, together with other team members measured the amount of Neu5Gc sugar in a variety of dairy and meat foods common in the French diet and calculated the daily Neu5Gc intake of 19,621 adults aged 18 and over, who reported all of their food intake online over a period of several days.

The research team then took a representative sample of 120 participants and tested the levels of the anti-Neu5Gc antibodies in their blood.

Based on these findings and the quantification of Neu5Gc sugar in various food products from France, Dr. Padler-Karavani and her team created an index called the Gcemic index. This index ranks foods whose excessive consumption can lead to an increase in the antibodies – and possibly to an increase in the risk of cancer.

“We found a significant correlation between high consumption of Neu5Gc from red meat and cheeses and increased development of those antibodies that heighten the risk of cancer,” Dr. Padler-Karavani says. “For years there have been efforts to find such a connection, but no one did. Here, for the first time, we were able to find a molecular link thanks to the accuracy of the methods used to measure the antibodies in the blood and the detailed data from the French diet questionnaires.”

Dr. Padler-Karavani adds that this combination of methods allowed the researchers to predict that those who eat a lot of red meat and cheese will develop high levels and a different variety of the antibodies, and therefore may be at higher risk for cancer – especially colorectal cancer, but other cancers as well.

References: Bashir, S., Fezeu, L.K., Leviatan Ben-Arye, S. et al. Association between Neu5Gc carbohydrate and serum antibodies against it provides the molecular link to cancer: French NutriNet-Santé study. BMC Med 18, 262 (2020). https://doi.org/10.1186/s12916-020-01721-8 link: https://bmcmedicine.biomedcentral.com/articles/10.1186/s12916-020-01721-8

Provided by American Friends of Tel Aviv University

Supercomputers Dig Into First Star Fossils (Astronomy)

No one has yet found the first stars.

They’re hypothesized to have formed about 100 million years after the Big Bang out of universal darkness from the primordial gases of hydrogen, helium, and trace light metals. These gases cooled, collapsed, and ignited into stars up to 1,000 times more massive than our sun. The bigger the star, the faster they burn out. The first stars probably only lived a few million years, a drop in the bucket of the age of the universe, at about 13.8 billion years. They’re unlikely to ever be observed, lost to the mists of time.

‘Galactic archaeology’ refers to the study of second generation stars to learn about the physical characteristics of the first stars, which disappeared only tens of millions of years after the Big Bang. A computational physics study modeled for the first time faint supernovae of metal-free first stars, yielding carbon-enhanced abundance patterns for star formation. Slice of density, temperature, and carbon abundance for a 13 solar mass progenitor model at times (left-right) 0.41, 15.22, and 29.16 million years after the supernovae explosion in a box with a side 2 kpc. ©Chiaki, et al.

As the metal-free first stars collapsed and exploded into supernovae, they forged heavier elements such as carbon that seeded the next generation of stars. One type of these second stars is called a carbon-enhanced metal-poor star. They’re like fossils to astrophysicists. Their composition reflects the nucleosynthesis, or fusion, of heavier elements from the first stars.

“We can get results from indirect measurements to get the mass distribution of metal-free stars from the elemental abundances of metal-poor stars,” said Gen Chiaki, a post-doctoral researcher in the Center for Relativistic Astrophysics, School of Physics, Georgia Tech.

Chiaki is the lead author of a study published in the September 2020 issue of the Monthly Notices of the Royal Astronomical Society. The study modeled for the first time faint supernovae of metal-free first stars, which yielded carbon-enhanced abundance patterns through the mixing and fallback of the ejected bits.

Their simulations also showed the carbonaceous grains seeding the fragmentation of the gas cloud produced, leading to formation of low-mass ‘giga-metal-poor’ stars that can survive to the present day and possibly be found in future observations.

“We find that these stars have very low iron content compared to the observed carbon-enhanced stars with billionths of the solar abundance of iron. However, we can see the fragmentation of the clouds of gas. This indicates that the low mass stars form in a low iron abundance regime. Such stars have never been observed yet. Our study gives us theoretical insight of the formation of first stars,” Chiaki said.

NSF-funded XSEDE awarded scientists access to the Stampede2 supercomputer at the Texas Advanced Computing Center (left) and the Comet supercomputer at the San Diego Supercomputer Center (center). The authors utilized the Georgia Tech PACE Hive cluster (right). ©TACC/SDSC/Georgia Tech.

The investigations of Wise and Chiaki are a part of a field called ‘galactic archaeology.’ They liken it to searching for artifacts underground that tell about the character of societies long gone. To astrophysicists, the character of long-gone stars can be revealed from their fossilized remains.

“We can’t see the very first generations of stars,” said study co-author John Wise, an associate professor also at the Center for Relativistic Astrophysics, School of Physics, Georgia Tech. “Therefore, it’s important to actually look at these living fossils from the early universe, because they have the fingerprints of the first stars all over them through the chemicals that were produced in the supernova from the first stars.”

Animation shows the enrichment process of carbon and iron from the supernova of a first-generation of star of 50 solar masses. The four panels show density, temperature, carbon and iron abundances. First, metals are dispersed in the ambient region in the almost spherical manner (< 14 Myr after the explosion). Then, the metals expand in the horizontal direction, while the expansion halts in the vertical direction. Eventually, the metals return to the central region again, where the next generation of stars form. Credit: Chiaki, et al.

“These old stars have some fingerprints of the nucleosynthesis of metal-free stars. It’s a hint for us to seek the nucleosynthesis mechanism happening in the early universe,” Chiaki said.

“That’s where our simulations come into play to see this happening. After you run the simulation, you can watch a short movie of it to see where the metals come from and how the first stars and their supernovae actually affect these fossils that live until the present day,” Wise said.

The scientists first modeled the formation of their first star, called a Population III or Pop III star, and ran three different simulations that corresponded to its mass at 13.5, 50, and 80 solar masses. The simulations solved for the radiative transfer during its main sequence and then after it dies and goes supernova. The last step was to evolve the collapse of the cloud of molecules spewed out by the supernova that involved a chemical network of 100 reactions and 50 species such as carbon monoxide and water.

The majority of the simulations ran on the Georgia Tech PACE cluster. They were also awarded computer allocations by the National Science Foundation (NSF)-funded Extreme Science and Engineering Discovery Environment (XSEDE). Stampede2 at the Texas Advanced Computing Center (TACC) and Comet at the San Diego Supercomputer Center (SDSC) ran some of the main sequence radiative transfer simulations through XSEDE allocations.

“The XSEDE systems Comet at SDSC and Stampede2 at TACC are very fast and have a large storage system. They were very suitable to conduct our huge numerical simulations,” Chiaki said.

“Because Stampede2 is just so large, even though it has to accommodate thousands of researchers, it’s still an invaluable resource for us,” Wise said. “We can’t just run our simulations on local machines at Georgia Tech.”

Chiaki said he was also happy with the fast queues on Comet at SDSC. “On Comet, I could immediately run the simulations just after I submitted the job,” he said.

Wise has been using XSEDE system allocations for over a decade, starting when he was a postdoc. “I couldn’t have done my research without XSEDE.”

XSEDE also provided expertise for the researchers to take full advantage of their supercomputer allocations through the Extended Collaborative Support Services (ECSS) program. Wise recalled using ECSS several years ago to improve the performance of the Enzo adaptive mesh refinement simulation code he still uses to solve the radiative transfer of stellar radiation and supernovae.

Slice of density, temperature, and carbon abundance for a progenitor model with a mass Mpr = 13 solar masses at the time tSN = 0.41 Myr (column a), 15.22 Myr (column b), and 29.16 Myr (column c) after the supernova explosion in a box with a side 2 kpc centered on the centroid of the MH. Credit: Chiaki, et al.

“Through ECSS, I worked with Lars Koesterke at TACC, and I found out that he used to work in astrophysics. He worked with me to improve the performance by about 50 percent of the radiation transport solver. He helped me profile the code to pinpoint which loops were taking the most time, and how to speed it up by reordering some loops. I don’t think I would have identified that change without his help,” Wise said.

Wise has also been awarded time on TACC’s NSF-funded Frontera system, the fastest academic supercomputer in the world. “We haven’t gotten to full steam yet on Frontera. But we’re looking forward to using it, because that’s even a larger, more capable resource.”

Wise added: “We’re all working on the next generation of Enzo. We call it Enzo-E, E for exascale. This is a total re-write of Enzo by James Bordner, a computer scientist at the San Diego Supercomputer Center. And it scales almost perfectly to 256,000 cores so far. That was run on NSF’s Blue Waters. I think he scaled it to the same amount on Frontera, but Frontera is bigger, so I want to see how far it can go.”

The downside, he said, is that since the code is new, it doesn’t have all the physics they need yet. “We’re about two-thirds of the way there,” Wise said.

He said that he’s also hoping to get access to the new Expanse system at SDSC, which will supersede Comet after it retires in the next year or so. “Expanse has over double the compute cores per node than any other XSEDE resource, which will hopefully speed up our simulations by reducing the communication time between cores,” Wise said.

According to Chiaki, the next steps in the research are to branch out beyond the carbon features of ancient stars. “We want to enlarge our interest to the other types of stars and the general elements with larger simulations,” he said.

Said Chiaki: “The aim of this study is to know the origin of elements, such as carbon, oxygen, and calcium. These elements are concentrated through the repetitive matter cycles between the interstellar medium and stars. Our bodies and our planet are made of carbon and oxygen, nitrogen, and calcium. Our study is very important to help understand the origin of these elements that we human beings are made of.”

References: Gen Chiaki, John H Wise, Stefania Marassi, Raffaella Schneider, Marco Limongi, Alessandro Chieffi, Seeding the second star – II. CEMP star formation enriched from faint supernovae, Monthly Notices of the Royal Astronomical Society, Volume 497, Issue 3, September 2020, Pages 3149–3165, https://doi.org/10.1093/mnras/staa2144 link: https://academic.oup.com/mnras/article-abstract/497/3/3149/5875932?redirectedFrom=fulltext

Provided by University Of Texas

Nasal Septum Surgery Can Affect Behaviour, Say Medics From RUDN University (Medicine)

A team of medics from RUDN University conducted an experiment on rats and confirmed that surgeries in the nasal cavity can cause behavioral changes, namely, make the animals timider. This effect is associated with an ANS reaction triggered by stress. The results of the experiment were published in the Journal of Physics: Conference Series.

A team of medics from RUDN University conducted an experiment on rats and confirmed that surgeries in the nasal cavity can cause behavioral changes, namely, make the animals timider. This effect is associated with an ANS reaction triggered by stress. ©RUDN University.

A deflected nasal septum can be corrected with a simple surgery that is often performed under local anesthesia. This procedure is recommended for patients with apnoea or chronic maxillitis. However, the side effects of the surgery include inflammations and edema. These processes and breathing difficulties caused by them can affect the autonomic nervous system (ANS) that regulates all involuntary functions of our body, such as digestion, blood supply, and heart rate maintenance. It is yet unknown what parts of the ANS react to septoplasty, and what behavioral changes such a reaction can lead to. A team of medics from RUDN University carried out experimental surgeries on rats and identified behavioral and physiological reactions to them.

For their experiment, the team chose ten healthy male rats. The animals received total anesthesia, and their septums were not actually cut but just scratched. No local painkillers or anti-inflammatory drugs were used after the surgery as they could have had an impact on the animals’ ANSs. To assess the changes in their behavior, the team placed the rats in an unfamiliar environment: the so-called “open field”, a square-shaped chamber with an open and well-lit center and holes in the center and all four corners. The open field test was performed once before the surgery and three times after it (in 2, 4, and 6 days, respectively). The medics also took electrocardiograms (ECG) of the rats before and after the procedure.

A minute by minute comparison of the animals’ behavior in the open field before and after the surgery showed a considerable reduction of activity in the latter case. After the procedure, the animals were more reluctant to examine the chamber or enter the holes, stood motionless for long periods of time, left more droppings, and rarely got on their hind legs. The ECG showed that the rats’ parasympathetic nervous systems that regulate relaxation and recovery processes were more active after the surgery.

According to the scientists, such behavioral changes may be due to post-surgical anxiety as well as physiological consequences such as inflammation, edema, and pain. Because of all these factors, the animals entered a depression-like state. The inflammation and shortage of oxygen activated the parasympathetic nervous system (PNS), and recovery processes started to dominate in the animals’ bodies. Based on a combination of behavioral and physiological data, the medics concluded that the nasal cavity surgery caused the rats to experience stress.

“Before this experiment, we had worked on a study on heart rate changes in human patients after septoplasty. I believe, these two works have a lot in common. Our earlier work had also shown increased PNS activity in certain cases. Post-surgical stress is likely to cause changes in the hippocampus area which leads to altered behavior. We need further studies to identify optimal parameters of local and total anesthesia and post-surgical pain management to prevent such consequences,” said PhD Igor Kastyro, a senior lecturer at the Department of Human Physiology, RUDN University.

References: I V Kastyro, A N Inozemtsev, P E Shmaevsky, G V Khamidullin, V Torshin, N Kovalenko, P D Pryanikov and I I Guseinov, “The impact of trauma of the mucous membrane of the nasal septum in rats on behavioral responses and changes in the balance of the autonomic nervous system (pilot study), Journal of Physics: Conference Series, Volume 1611, The XVII International Conference on Prospects of Fundamental Sciences Development 21-24 April 2020. https://iopscience.iop.org/article/10.1088/1742-6596/1611/1/012054

Provided by RUDN University

Cord Blood DNA Can Hold Clues For Early ASD Diagnosis And Intervention (Medicine)

A new study led by UC Davis MIND Institute researchers found a distinct DNA methylation signature in the cord blood of newborns who were eventually diagnosed with autism spectrum disorder (ASD). This signature mark spanned DNA regions and genes linked to early fetal neurodevelopment. The findings may hold clues for early diagnosis and intervention.

“We found evidence that a DNA methylation signature of ASD exists in cord blood with specific regions consistently differentially methylated,” said Janine LaSalle, lead author on the study and professor of microbiology and immunology at UC Davis.

The study published Oct. 14 in Genome Medicine also identified sex-specific epigenomic signatures that support the developmental and sex-biased roots of ASD.

The U.S. Centers for Disease Control and Prevention (CDC) estimates that one in 54 children are diagnosed with ASD, a complex neurological condition linked to genetic and environmental factors. It is much more prevalent in males than females.

The role of the epigenome in DNA functioning

The epigenome is a set of chemical compounds and proteins that tell the DNA what to do. These compounds attach to DNA and modify its function. One such compound is CH3 (known as the methyl group) that could lead to DNA methylation. DNA methylation can change the activity of a DNA segment without changing its sequence. Differentially methylated regions (DMRs) are areas of DNA that have significantly different methylation status.

The epigenome compounds do not change the DNA sequence but affect how cells use the DNA’s instructions. These attachments are sometimes passed on from cell to cell as cells divide. They can also be passed down from one generation to the next. The neonatal epigenome has the potential to reflect past interactions between genetic and environmental factors during early development. They may also influence future health outcomes.

Finding factors in fetal cord blood that might predict autism

The researchers studied the development of 152 children born to mothers enrolled in the MARBLES and EARLI studies. These mothers had at least one older child with autism and were considered at high risk of having another child with ASD. When these children were born, the mothers’ umbilical cord blood samples were preserved for analysis. At 36 months, these children got diagnostic and developmental assessments. Based on these, the researchers grouped the children under “typically developing” (TD) or “with ASD.”

The researchers also analyzed the umbilical cord blood samples taken at birth from the delivering mothers. They performed whole-genome sequencing of these blood samples to identify an epigenomic signature or mark of ASD at birth. They were checking for any patterns of DNA-epigenome binding that could predict future ASD diagnosis.

They split the samples into discovery and replication sets and stratified them by sex. The discovery set included samples from 74 males (39 TD, 35 ASD) and 32 females (17 TD, 15 ASD). The replication set was obtained from 38 males (17 TD, 21 ASD) and eight females (3TD, 5 ASD).

Using the samples in the discovery set, the researchers looked to identify specific regions in the genomes linked to ASD diagnosis. They tested the DNA methylation profiles for DMRs between ASD and TD cord blood samples. They mapped the DMRs to genes and assessed them in gene function, tissue expression, chromosome location and overlap with prior ASD studies. They later compared the results between discovery and replication sets and between males and females.

Cord blood to reveal insights into genes related to ASD

The researchers identified DMRs stratified by sex that discriminated ASD from TD cord blood samples in discovery and replication sets. They found that seven regions in males and 31 in females replicated, and 537 DMR genes in males and 1762 DMR genes in females replicated by gene association. These DMRs identified in cord blood overlapped with binding sites relevant to fetal brain development. They showed brain and embryonic expression and X chromosome location and matched with prior epigenetic studies of ASD.

“Findings from our study provide key insights for early diagnosis and intervention,” LaSalle said. “We were impressed by the ability of cord blood to reveal insights into genes and pathways relevant to the fetal brain.”

The researchers pointed out that these results will require further replication before being used diagnostically. Their study serves as an important proof of principle that the cord blood methylome is informative about future ASD risk.

References: Mordaunt et al. (2020). Cord blood DNA methylome in newborns later diagnosed with autism spectrum disorder reflects early dysregulation of neurodevelopmental and X-linked genes, Genome Medicine, doi: https://doi.org/10.1186/s13073-020-00785-8

Provided by University Of California davis health

Rapid Method Of Isolating Tumor-targeting T Cells Could Propel Personalized Cancer Treatment (Oncology / Medicine)

A technique developed at Scripps Research seeks to fill an unmet need among scientists and doctors who need faster, more precise tools to identify useful tumor-infiltrating immune cells.

A cell infused with a special enzyme interacts with a tumor-targeting immune cell–a process that enables the immune cells to be easily captured and leveraged for a cancer treatment. Image courtesy of the Wu laboratory at Scripps Research.

When it comes to defeating cancer, some immune cells are mightier than others. But even the best-trained eye and today’s advanced scientific tools have trouble discerning the most powerful tumor-fighting cells from the rest.

A new technique developed at Scripps Research by scientist Peng Wu, PhD, aims to change that–offering a new platform that could propel personalized cancer treatments that have been hindered due to the challenges of isolating the most useful immune cells in patients. The development is published October 22 in Cell.

“In many new and emerging personalized cancer therapies, the key to success is finding the sometimes-elusive T cells that are directly targeting the tumor, then creating more of those cells outside of patients’ bodies and re-introducing them for tumor treatment,” says Wu, associate professor in the Department of Molecular Medicine and senior author of the study. “With our simple method to detect and isolate tumor-reactive immune cells, my hope is that we can advance personalized immunotherapy treatments that are now either too costly or laborious to reach their potential.”

The method is called FucoID, named after the enzyme fucosyltransferase that plays a starring role in “tagging” the surface of sought-after immune cells so they can be seen and captured. The enzyme is loaded onto dendritic cells, a type of immune cell that presents tumor-specific material to the desired T cells. When the cells interact, the enzyme transfers a tag to the tumor-fighting cells so scientists can detect them with a fluorescent probe and extract them from the sample.

In experiments involving mice, the approach successfully identified multiple types of so-called “tumor antigen-specific T cells,” including CD4+ and CD8+ T cells that infiltrate tumors and attack from within. These cells are central to certain cancer immunotherapies–including checkpoint inhibitors and treatments known as adoptive TIL (tumor infiltrating lymphocyte) transfer therapies.

“This approach removes a significant barrier to studying tumor-specific T cells and will be immensely useful for both basic scientists and clinicians,” says John Teijaro, PhD, associate professor in the Department of Immunology and Microbiology and co-author of the study.

“This study also highlights how the highly collaborative environment at Scripps Research fosters innovative solutions to intractable problems.”

The FucoID process of isolating the appropriate cells takes only one day, compared with four or five weeks using current methods, according to Wu. “Once we isolate them, we can expand them into millions or billions of cells to construct a treatment or simply to study them,” he says.

Having the ability to quickly take stock of these cells in a patient can also help doctors predict therapeutic success or treatment progress, he says. And doing any of these things faster than today’s methods, which rely on bioinformatics or genetic manipulations, can make a big difference to patients.

Wu is now collaborating with clinicians at UC San Diego to use FucoID to isolate the desired T cells from human patient tumor samples, with the goal of eventually applying the platform to a clinical trial for a cancer treatment.

“We believe FucoID has potential to be translated to a clinical setting for the detection and isolation of tumor-reactive immune cells, ultimately paving the way for lowering the cost and accessibility of personalized cancer treatment,” Wu says.

References: Zilei Liu, Jie P. Li, Mingkuan Chen, Wei Li, John R. Teijaro, Peng Wu, “Detecting Tumor Antigen-Specific T Cells via Interaction-Dependent Fucosyl- Biotinylation”, Cell, 2020. DOI:https://doi.org/10.1016/j.cell.2020.09.048 link: https://www.cell.com/cell/fulltext/S0092-8674(20)31245-9

Provided by Scripps

Bat-winged Dinosaurs That Could Glide (Paleontology)

Despite having bat-like wings, two small dinosaurs, Yi and Ambopteryx, struggled to fly, only managing to glide clumsily between the trees where they lived, according to a new study led by an international team of researchers, including McGill University Professor Hans Larsson. Unable to compete with other tree-dwelling dinosaurs and early birds, they went extinct after just a few million years. The findings, published in iScience, support that dinosaurs evolved flight in several different ways before modern birds evolved.

Life reconstruction of the bat-winged scansoriopterygid dinosaur Ambopteryx in a glide. Image credit: Gabriel Ugueto.

“We know some dinosaurs could fly before they evolved into birds,” says Professor Larsson, Director of McGill’s Redpath Museum. “What this shows us is that at least one lineage of dinosaurs experimented with a completely different mode of aerial locomotion. Gliding evolved countless times in arboreal amphibians, mammals, lizards, and even snakes – and now we have an example of dinosaurs.”

Yi and Ambopteryx were small animals from the Late Jurassic of China, living about 160 million years ago. Weighing in at about half a kilogram, they are unusual theropod dinosaurs. Theropods are carnivorous dinosaurs that include all birds alive today. Most theropods were ground-loving carnivores, but Yi and Ambopteryx were at home in the trees and lived on a diet of insects, seeds, and plants.

Map of the skeleton and preserved soft tissues of Yi. Image credit: Dececchi et al. 2020.

“Once birds got into the air, these two species were so poorly capable of being in the air that they just got squeezed out,” says lead author Thomas Dececchi, an assistant professor of biology at Mount Marty University. “Maybe you can survive a few million years underperforming, but you have predators from the top, competition from the bottom, and even some small mammals adding into that, squeezing them out until they disappeared.”

Little creatures could glide, not fly

Curious about how these animals could have flown, the researchers, scanned fossils using Laser-Stimulated Fluorescence (LSF), a technique that uses laser light to pick up soft tissue details of their wing membranes that can’t be seen with standard white light. Later, the team used mathematical models to predict how they might have flown, testing different variables like weight, wingspan, wing shape, and muscle placement.

“The results are clear these animals were not able to fly like birds,” says Larsson. “They didn’t have adaptations to even get close to the physical thresholds for powered flight, but their weird membranous wings do give them enough of an aerofoil to have glided. They are not comparable to living gliding squirrels or lizards but seem to have come up with a really novel way of getting a large enough wing membrane.”

Graphical summary of the major findings of the new study. Image credit: Dececchi et al. 2020.

Although gliding is not an efficient form of flight since it can only be done if the animal has already climbed to a high point, it probably did help Yi and Ambopteryx stay out of danger while they were still alive.

“Living gliders don’t travel long distances through the air,” says Dececchi. “It’s not efficient, but it can be used as an escape hatch. It’s not a great thing to do, but sometimes it’s a choice between losing a bit of energy and being eaten. Once they were put under pressure, they just lost their space. They couldn’t win on the ground. They couldn’t win in the air. They were done.”

The researchers are now looking more closely at the musculoskeletal anatomy of these bat-winged and other feathered dinosaurs that evolved around the origin of birds. “The diversity of dinosaurs just before the origin of birds amazes me,” Larsson says. “We used to think of birds evolving as a linear trend from their ground-dwelling dinosaur ancestry. We can know revise this textbook scenario to one that had an explosive diversity of experimentation, with dinosaurs evolving powered flight several times independently from birds, many having fully feathered wings but with bodies too heavy or wings too small to have gotten off the ground, and now, a weird bat-winged group of dinosaurs that were not only the first arboreal dinosaurs, but ones that glided! I feel like we are still just scratching the surface.”

References: “Aerodynamics show membranous-winged theropods were a poor gliding dead-end” by T. Alexander Dececchi, Arindam Roy, Michael Pittman, Thomas G. Kaye, Xing Xu, Michael B. Habib, Hans C.E. Larsson, Xiaoli Wang, and Xiaoting Zheng is published in iScience. DOI: http://dx.doi.org/10.1016/j.isci.2020.101574

Provided by McGill University

Type 1 Diabetes: Tannic Acid Encapsulation Protects Transplanted Islets From Rejection (Medicine)

Type 1 diabetes, or T1D, results from the autoimmune destruction of the insulin-producing cells of the pancreas. People with T1D require exogenous insulin and suffer swings in the levels of glucose in the blood that impact life expectancy and increase risks of cardiovascular disease, neuropathies and kidney failure.

Eugenia Kharlampieva. ©UAB – Steve Wood.

One therapy is promising — transplanting pancreatic islets from cadavers. But this requires immunosuppression, and reactivated autoimmunity leads to low graft viability and function after five years.

Now, a team of University of Alabama at Birmingham researchers has shown a simple way to protect transplanted islets, by coating them with a thin skin of alternating layers of two biopolymers. As reported in the journal Diabetes, this coating delays allograft and autoimmune-mediated rejection in mouse models of T1D.

“Our approach to inhibit proinflammatory immune responses with poly(N-vinylpyrrolidone)-tannic acid-encapsulated islets without systemic immunosuppression is a significant advancement toward successful islet transplants in humans,” said senior authors Hubert Tse, Ph.D., and Eugenia Kharlampieva, Ph.D.

The biocompatible poly (N-vinylpyrrolidone)-tannic acid, or PVPON and tannic acid, or TA, are coated onto the islets in multiple alternating layers that are thin enough to allow oxygen and nutrients to easily reach the cells. This nano-thin encapsulation is about 120 times thinner than a sheet of plastic cling wrap. The key to its autoimmune protection, the UAB researchers say, are the layers of TA. This phenolic compound can scavenge reactive oxygen species and has an anti-inflammatory effect.

Oxidative stress from reactive oxygen species, or ROS, was already known to play a key role in the activation of alloreactive and autoreactive immunity toward engrafted islets, and the insulin-producing beta cells of the islets are more sensitive to ROS than many other cells of the body.

In autoimmune transplant experiments for the UAB study, more than half of the (PVPON/TA)-encapsulated grafts survived at 70 days post-transplant, while less than a quarter of the non-encapsulated grafts survived. In alloimmune transplant experiments, where the islets came from a different strain of mice, about 40 percent of the encapsulated grafts survived at 120 days post-transplant, while all of the unencapsulated grafts were rejected in less than 50 days.

In both types of transplantation, systemic immunosuppression was absent. The (PVPON/TA)-encapsulated islets maintained euglycemia significantly longer than non-encapsulated islets, and the grafts were immunomodulatory.

The mice receiving the encapsulated grafts had significant decreases in immune cell infiltration, ROS synthesis, inflammatory chemokines, cytokines and CD8 T cell infiltration, as compared to mice getting the non-encapsulated islets.

ROS is known to promote proinflammatory M1 macrophages differentiation; in contrast, the mice receiving the encapsulated islets showed an increase in anti-inflammatory M2 macrophages.

Tse and Kharlampieva say much more can be done to improve immunosuppression by the encapsulation and extend that protection to other sources of islets that are more readily available than human cadaver islets.

“PVPON/TA coatings can be modified to increase the number of layers of PVPON and TA for encapsulation, complexed with immune inhibitory receptors, including CTLA-4, PD-L1, and/or anti-inflammatory cytokines like IL-10 and TGF-beta, to further enhance localized immunosuppression,” they said. “The use of PVPON/TA coatings is not limited to encapsulation of human islets, as our preliminary studies also demonstrate that PVPON/TA encapsulation does not compromise neonatal porcine islet function and can also be expanded to include human stem cell-derived pancreatic beta-cells.”

At UAB, Tse is an associate professor in the UAB Department of Microbiology, and Kharlampieva is a professor of chemistry in the UAB College of Arts and Sciences.

Co-authors with Tse and Kharlampieva for the Diabetes study, “Localized immunosuppression with tannic acid encapsulation delays islet allograft and autoimmune-mediated rejection,” are Jessie M. Barra, UAB Department of Microbiology, and Veronika Kozlovskaya, Ph.D., UAB Department of Chemistry.

References: Jessie M. Barra, Veronika Kozlovskaya, Eugenia Kharlampieva, Hubert M. Tse, “Localized Immunosuppression With Tannic Acid Encapsulation Delays Islet Allograft and Autoimmune-Mediated Rejection”, Diabetes Sep 2020, 69 (9) 1948-1960; DOI: 10.2337/db20-0248 link: https://diabetes.diabetesjournals.org/content/69/9/1948.article-info

Provided by University of Alabama At Birmingham

Turning Streetwear Into Solar Power Plants (Material Science)

Our hunger for energy is insatiable, it even continues to rise with the increasing supply of new electronic gadgets. What’s more, we are almost always on the move and thus permanently dependent on a power supply to recharge our smartphones, tablets and laptops. In the future, power sockets (at least for this purpose) could possibly become obsolete. The electricity would then come from our own clothes. By means of a new polymer that is applied on textile fibers, jackets, T-shirts and the like could soon function as solar collectors and thus as a mobile energy supply.

The newly developed solar concentrator when irradiated with blue LED light: The polymer material is so flexible that it can be bent with tweezers. ©EMPA

Making luminescent materials flexible

Materials capable of using indirect or ambient light for energy generation are already being used in the solar industry. These materials contain special luminescent materials and are called “Luminescent Solar Concentrators”, or LSC for short. The luminescent materials in the LSC capture diffuse ambient light and transmit its energy to the actual solar cell, which then converts light into electrical energy. However, LSCs are currently only available as rigid components and are unsuitable for use in textiles because they are neither flexible nor permeable to air and water vapor. An interdisciplinary research team led by Luciano Boesel from the Laboratory for Biomimetic Membranes and Textiles has now succeeded in incorporating several of these luminescent materials into a polymer that provides precisely this flexibility and air permeability.

Well-known polymer with sophisticated properties

This new material is based on Amphiphilic Polymer Co-Networks, or APCN for short, a polymer that has long been known in research and is already available on the market in the form of silicone-hydrogel contact lenses. The special properties of the polymer – permeability to air and water vapor as well as flexibility and stability – are also beneficial to the human eye and are based on special chemical properties. “The reason we chose exactly this polymer is the fact that we are capable of incorporating two immiscible luminescent materials at the nano scale and let them interact with each other. There are, of course, other polymers, in which these materials could be integrated; but this would lead to aggregation, and the production of energy would thus not be possible», explains Boesel.

Two luminescent materials (red and green) are incorporated into a polymer at the nano scale. This polymer is flexible, permeable and at the same time acts as a solar concentrator for energy generation, which can be applied to textile fibers. Image: Empa.
In the project different luminescent materials were tested for their potential for energy generation. Image: Empa.

Bright solar concentrators for clothing

In collaboration with colleagues from two other Empa labs, Thin Films and Photovoltaics and Advanced Fibers, Boesel’s team added two different luminescent materials to the gel tissue, turning it into a flexible solar concentrator. Just as on large-scale (rigid) collectors, the luminescent materials capture a much wider spectrum of light than is possible with conventional photovoltaics. The novel solar concentrators can be applied to textile fibers without the textile becoming brittle and susceptible to cracking or accumulating water vapor in the form of sweat. Solar concentrators worn on the body offer an immense benefit for the ever-increasing demand for energy, especially for portable devices.

References: Chieh-Szu Huang, Luciano F. Boesela et al., “Nano-domains assisted energy transfer in amphiphilic polymer conetworks for wearable luminescent solar concentrators”, Nano Energy, Volume 76, October 2020, 105039 Doi:
https://doi.org/10.1016/j.nanoen.2020.105039 link: https://www.sciencedirect.com/science/article/pii/S2211285520306169?via%3Dihub

Provided by EMPA