Scientists Create a Longer-Lasting Exciton that May Open New Possibilities in Quantum Information Science

Alessandra Lanzara at Berkeley Lab.
Photo Credit: Mark Joseph Hanson

In a new study, scientists have observed long-lived excitons in a topological material, opening intriguing new research directions for optoelectronics and quantum computing. 

Excitons are charge-neutral quasiparticles created when light is absorbed by a semiconductor. Consisting of an excited electron coupled to a lower-energy electron vacancy or hole, an exciton is typically short-lived, surviving only until the electron and hole recombine, which limits its usefulness in applications. 

“If we want to make progress in quantum computing and create more sustainable electronics, we need longer exciton lifetimes and new ways of transferring information that don’t rely on the charge of electrons,” said Alessandra Lanzara, who led the study. Lanzara is a senior faculty scientist at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) and a UC Berkeley physics professor. “Here we’re leveraging topological material properties to make an exciton that is long lived and very robust to disorder.” 

In a topological insulator, electrons can only move on the surface. By creating an exciton in such a material, the researchers hoped to achieve a state in which an electron trapped on the surface was coupled to a hole that remained confined in the bulk. Such a state would be spatially indirect – extending from the surface into the bulk – and could retain the special spin properties inherent to topological surface states. 

A simple paper test could offer early cancer diagnosis

MIT engineers have designed a new nanoparticle sensor that can enable cancer diagnosis with a simple urine test. The nanoparticles (blue) carry DNA barcodes (zigzag lines) that can be cleaved by cancer-associated proteases in the body (pac-man shapes). Once cleaved, the DNA barcodes can be detected in a urine sample.
Illustration Credit: Courtesy of the researchers. Edited by MIT News

MIT engineers have designed a new nanoparticle sensor that could enable early diagnosis of cancer with a simple urine test. The sensors, which can detect many different cancerous proteins, could also be used to distinguish the type of a tumor or how it is responding to treatment.

The nanoparticles are designed so that when they encounter a tumor, they shed short sequences of DNA that are excreted in the urine. Analyzing these DNA “barcodes” can reveal distinguishing features of a particular patient’s tumor. The researchers designed their test so that it can be performed using a strip of paper, similar to an at-home Covid test, which they hope could make it affordable and accessible to as many patients as possible.

“We are trying to innovate in a context of making technology available to low- and middle-resource settings. Putting this diagnostic on paper is part of our goal of democratizing diagnostics and creating inexpensive technologies that can give you a fast answer at the point of care,” says Sangeeta Bhatia, the John and Dorothy Wilson Professor of Health Sciences and Technology and of Electrical Engineering and Computer Science at MIT and a member of MIT’s Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science.

Study links nutrients, brain structure, cognition in healthy aging

In a study of older adults, a research team led by, from left, Christopher Zwilling, Tanveer Talukdar and Aron Barbey found that blood markers of two saturated fatty acids, along with certain omega-6, -7 and -9 fatty acids, correlated with better scores on tests of memory and were associated with larger brain structures in the frontal, temporal, parietal and insular cortices. 
Photo Credit: Fred Zwicky

In a new study, scientists explored the links between three measures known to independently predict healthy aging: nutrient intake, brain structure and cognitive function. Their analysis adds to the evidence that these factors jointly contribute to brain health in older adults. 

Reported in the Journal of Nutrition, the study found that blood markers of two saturated fatty acids, along with certain omega-6, -7 and -9 fatty acids, correlated with better scores on tests of memory and with larger brain structures in the frontal, temporal, parietal and insular cortices. 

While other studies have found one-to-one associations between individual nutrients or classes of nutrients and specific brain regions or functions, very little research takes a comprehensive look at brain health, cognition and broad dietary patterns overall, said Aron Barbey, a professor of psychology, bioengineering and neuroscience at the University of Illinois Urbana-Champaign who led the study with postdoctoral researcher Tanveer Talukdar and psychology research scientist Chris Zwilling. The three co-authors are all affiliated with the Beckman Institute for Advanced Science and Technology at the U. of I. 

Antimicrobial use in agriculture can breed bacteria resistant to first-line human defenses

E. coli bacteria
Image Credit: itstheeighthhorcrux

A new study led by the University of Oxford has shown that overuse of antimicrobials in livestock production can drive the evolution of bacteria more resistant to the first line of the human immune response. The results, published today in the journal eLife, indicate that farmed pigs and chickens could harbor large reservoirs of cross-resistant bacteria, capable of fueling future epidemics.

Drug-resistant infections are one of the most serious threats to global health, and there is an urgent need to develop new, effective antimicrobials. One promising solution could be antimicrobial peptides (AMPs). These are compounds naturally produced by most living organisms, including animals, and have important roles in innate immunity, our first line of defense against bacterial infections.

However, some AMPs are also used widely in livestock production, both to control infections and as growth promoters. This has raised concerns that agricultural AMP use may generate cross-resistant bacteria that could then overcome the human innate immune response.

 In this new study, led by the University of Oxford, researchers have demonstrated that evolution of such cross-resistant bacteria is not only possible, but also highly likely.

Condensed Matter Physics Inspires a New Model of Cellular Behavior

Model illustrating how cells exert pressure on one another, leading to extrusion.
Image Credit: Courtesy of S. Monfared

Cells are expert cooperators and collaborators. To maintain tissue health, cells talk to each other, exert pressure on each other, and kick out cells that are not contributing to the overall well-being of the collective. When it's time to get rid of a cell, the collective group initiates a process called cell extrusion. Cells can be extruded for a number of reasons—they could be cancerous, or old, or they simply could be overcrowding other cells. Extrusion is a necessary process for tissues to maintain health and integrity.

Biologists have long studied the biochemical cues and signals that underly cell extrusion, but the mechanical, physical forces involved are poorly understood.

Now, inspired by the mechanics of a phase of matter called liquid crystals, researchers have developed the first three-dimensional model of a layer of cells and the extrusion behavior that emerges from their physical interactions. From this new model, the team discovered that the more a cell is squeezed by its neighbors in a particular symmetric way, the more likely it is to get extruded from the group.

Mysterious underwater acoustic world of British ponds revealed in new study

Old Sneed Park
Photo Credit: Dr Jack Greenhalgh

The previously hidden and diverse underwater acoustic world in British ponds has been revealed by a team of researchers at the University of Bristol.

Ponds are magnets for life and a lot of that life is very noisy. Water beetles, bugs, fish, frogs, and even aquatic plants all produce sound creating a diverse underwater orchestra that scientists are only just starting to understand.

Acoustic monitoring has been shown to effectively survey birds and monkeys in rainforests, and marine mammals in the oceans. However, freshwater environments have remained largely unexplored despite their diverse soundscapes.

“Ponds are packed full of bizarre and mysterious sounds made by scratching aquatic insects, booming fish, and popping plants. It’s like an underwater disco!” explained lead author Dr Jack Greenhalgh from Bristol’s School of Biological Sciences.

To better understand these mysterious soundscapes, the team collected 840 hours of underwater sound recordings from five ponds in the southwest of England using an underwater microphone (a hydrophone).

Genetically Modified Plants Grow Better in Arid and Saline Conditions

Tobacco is one of the most well-studied plants by scientists.
Photo Credit: Rodion Narudinov

Russian scientists have modified tobacco. They added the AtGSTF11 gene and improved the plant's resistance to adverse conditions. These adverse conditions include low temperatures, drought and salty soil. Model plants with the new gene used in the experiments showed increased vitality. The scientists have published a description of their experiments in the Russian Journal of Plant Physiology.

Plant stress (caused by a variety of factors - drought, temperature, contaminated soil, etc.) ends at the cellular level with oxidative stress: reactive oxygen species are formed in the cell. They destroy proteins, disrupt the structure of DNA and lead to cell death or interfere with vital functions, the scientists add. There are cellular mechanisms that prevent the development of oxidative stress - low-molecular antioxidant compounds, proteins (antioxidant enzymes), glutathione.

"Glutathione is a short sulfur-containing peptide that plays an important role in protecting plants from stress. It is formed, then cycled into oxidized and reduced forms, and so on. This is the glutathione cycle. In this process, reactive oxygen species are eliminated and plant cells do not die. A number of genes are involved in this cycle. We added another gene, glutathione S-transferase, and got a more viable plant," says Bulat Kuluev, Head of the Plant Genomics Laboratory at the Institute of Biochemistry and Genetics (Subdivision of the Ufa Federal Research Centre of the Russian Academy of Sciences).

Highly sensitive Raman probe detects enzyme expression in heterogeneous tissues

Raman imaging offers a greater potential for detecting multiple enzyme activities than fluorescence imaging, demonstrate Tokyo Tech researchers by developing 9CN-rhodol-based activatable Raman probes using a novel mechanism for Raman signal activation. The strategy allows a synthesis of highly activatable Raman probes with high aggregation and multiplexing ability, making it a promising tool for extending the range of Raman probes for the detection of multiple enzyme activities in heterogeneous biological tissues.

The involvement of enzymes in a wide range of biological activities makes them ideal biomarkers for the detection of diseases. In fact, cancer-specific diagnostic technologies use fluorescence imaging for detecting upregulated cancer-associated enzymes in the affected cells. Moreover, since tumor tissues are heterogenous, detecting multiple enzyme activities simultaneously could allow precise cancer visualization and diagnosis. However, the inability to detect multiple enzyme activities can potentially limit the application of fluorescence imaging in heterogeneous tumor tissues and other complex biological phenomena.

Super-charged textile sets trends

The fabric becomes conductive when coated with with a special 'breathable' metallic layer.
Photo Credit: Flinders University

Scientists from around the world have developed a simple metallic coating treatment for clothing or wearable textiles which can repair itself, repel bacteria from the wearer and even monitor a person’s electrocardiogram (ECG) heart signals. 

Researchers from North Carolina State University, Flinders University and South Korea say the conductive circuits created by liquid metal (LM) particles can transform wearable electronics and open doors for further development of human-machine interfaces, including soft robotics and health monitoring systems.  

The ‘breathable’ electronic textiles have special connectivity powers to ‘autonomously heal’ itself even when cut, says the US team led by international expert in the field, Professor Michael Dickey. 

When the coated textiles are pressed with significant force, the particles merge into a conductive path, which enables the creation of circuits that can maintain conductivity when stretched. 

Researchers Identify a New Genetic Culprit in Canine Bladder Cancers

Photo Credit: Lucie Helešicová

Researchers have identified new genetic mutations linked to a subset of canine bladder cancers. Their findings have implications both for early cancer detection and for targeted treatments in dogs and humans.

Previous research showed that 85% of canine urothelial carcinomas (a type of bladder cancer) share a specific mutation in a gene named BRAF. This mutation (known as V595E) is caused by an error in BRAF’s genetic code, where a normal ‘T’ nucleotide in the DNA sequence is substituted by an ‘A’. The BRAF V595E mutation results in abnormal activation of a genetic signaling pathway called MAPK, leading to uncontrolled cellular growth, or proliferation.

“Essentially, BRAF V595E generates an abnormal protein that instructs the cells to keep dividing, forming a tumor. So, if this single nucleotide substitution in the BRAF gene is detected in 85% of all canine urothelial carcinomas, why is it not in all of them?” asks Matthew Breen, Oscar J. Fletcher Distinguished Professor of Comparative Oncology Genetics at North Carolina State University and corresponding author of the research. “Pathologists see no difference between those cancers with this mutation and those without, so what’s going on with that other 15%?”

Pioneering research sheds new light on the origins and composition of planet Mars

The InSight mission’s seismometer, though coated by several years of Martian dust, was able to capture recordings of seismic events from the far side of the planet. NASA's InSight Mars lander acquired this image of the area in front of the lander using its lander-mounted Instrument Context Camera (ICC).
Image Credit: NASA/JPL-Caltech

A new study has uncovered intriguing insights into the liquid core at the center of Mars, furthering understanding of the planet’s formation and evolution.

The research, led by the University of Bristol and published in the journal Proceedings of the National Academy of Sciences of the US, reveals the first-ever detections of sound waves travelling into the Martian core. Measurements from this acoustic energy, called seismic waves, indicate its liquid core is slightly denser and smaller than previously thought, and comprises a mixture of iron and numerous other elements.

The findings are all the more remarkable, as the research mission was initially only scheduled to last for a little over one Mars year (two Earth years). Despite Martian storms hastening the accumulation of dust and reducing power to the NASA InSight Mars lander, NASA extended its stay, so geophysical data, including signals of marsquakes, continued to be gathered until the end of last year.

Earliest animal likely used chemical signaling to evolve into multicellular organism

J.P. Gerdt is an assistant professor of chemistry in the IU Bloomington College of Arts and Sciences.
 Photo Credit: Courtesy of J.P. Gerdt

The earliest animal likely used chemical signaling to evolve from a single cell to a multicellular organism, according to a study led by an Indiana University Bloomington scientist. The findings provide new information about how one of the biggest transitions in the history of life on earth likely occurred.

J.P. Gerdt, assistant professor of chemistry in the IU Bloomington College of Arts and Sciences, led the study, along with Núria Ros-Rocher of the Institute of Evolutionary Biology in Barcelona, Spain. Their findings are published in the Proceedings of the National Academy of Sciences.

“The general view is that animals evolved from a unicellular organism, and this research helps explain how that may have happened and how those cells chose whether to be together or on their own,” Gerdt said. “Our results help us understand more about the first animals and their ancestors.”

Mudskippers Could Be Key to Understanding Evolution of Blinking

Indian mudskipper P. septemradiatus
Photo Credit: Courtesy of Georgia Institute of Technology

Blinking is crucial for the eye. It’s how animals clean their eyes, protect them, and even communicate. But how and why did blinking originate? Researchers at the Georgia Institute of Technology, Seton Hill University, and Pennsylvania State University studied the mudskipper, an amphibious fish that spends most of its day on land, to better understand why blinking is a fundamental behavior for life on land.

Although mudskippers are distantly related to tetrapods, the group that includes humans and other four-limbed vertebrates, researchers believed studying the fish could unlock how blinking evolved as these animals began to move on land. 

The research team, which included several undergraduates, published their findings in the paper, “The Origin of Blinking in Both Mudskippers and Tetrapods Is Linked to Life on Land,” in Proceedings of the National Academies of Science.

“By comparing the anatomy and behavior of mudskippers to the fossil record of early tetrapods, we argue that blinking emerged in both groups as an adaptation to life on land,” said Tom Stewart, an assistant professor at Penn State and an author of the paper. “These results help us understand our own biology and raise a whole set of new questions about the variety of blinking behaviors we see in living species.”

Researchers discover new self-assembled crystal structures

 Conceptual image showcasing several interaction potential shapes, represented by stems, that will lead to the self-assembly of new low-coordinated crystal structures, represented by flowers. 
Image Credit: Hillary Pan

Using a targeted computational approach, researchers in the Department of Materials Science and Engineering at Cornell have found more than 20 new self-assembled crystal structures, none of which had been observed previously.

The research, published in the journal ACS Nano under the title “Targeted Discovery of Low-Coordinated Crystal Structures via Tunable Particle Interactions,” is authored by Ph.D. student Hillary Pan and her advisor Julia Dshemuchadse, assistant professor of materials science and engineering.

“Essentially we were trying to figure out what kinds of new crystal structure configurations we can self-assemble in simulation,” Pan said. “The most exciting thing was that we found new structures that weren’t previously listed in any crystal structure database; these particles are actually assembling into something that nobody had ever seen before.”

The team conducted a targeted search for previously unknown low-coordinated assemblies within a vast parameter space spanned by particles interacting via isotropic pair potentials, the paper states. “Low-coordinated structures have anisotropic local environments, meaning that the geometries are highly directional, so it’s incredible that we’re able to see such a variety of these types of structures using purely non-directional interactions,” said Pan.

New insights on the risk of atrial fibrillation in children and adolescents

Image Credit: PublicDomainPictures

Researchers at Karolinska Institutet have investigated the relationship between premature birth and fetal growth and the risk of developing atrial fibrillation up to middle age. The study, published in JAMA Pediatrics, shows a slightly increased risk, especially in people who were born prematurely or who were large at birth. Low fetal growth was associated with an increased risk of atrial fibrillation only up to the age of 18.

For a few decades, the prevalence of atrial fibrillation at a young age has increased slightly, albeit from low levels.

"Atrial fibrillation at a young age can impose a heavy socio-economic burden on the individual, and more knowledge is needed about the underlying causes of the disease. Our findings can highlight the need to monitor and prevent the disease in more groups with an increased risk of cardiovascular disease", said the study's first author Fen Yang, doctoral student at Department of Global Public Health, Karolinska Institutet.