The Building Blocks for Exploring New Exotic States of Matter

Using the High Flux Isotope Reactor’s DEMAND instrument, neutron scattering studies identified the crystal & magnetic structure of an intrinsic ferromagnetic topological insulator MnBi8Te13. The last column of inset shows its crystal & magnetic structures
Image credit: Oak Ridge National Laboratory.

Topological insulators act as electrical insulators on the inside but conduct electricity along their surfaces. Researchers study some of these insulators’ exotic behavior using an external magnetic field to force the ion spins within a topological insulator to be parallel to each other. This process is known as breaking time-reversal symmetry. Now, a research team has created an intrinsic ferromagnetic topological insulator. This means the time-reversal symmetry is broken without applying a magnetic field. The team employed a combination of synthesis, characterization tools, and theory to confirm the structure and properties of new magnetic topological materials. In the process, they discovered an exotic axion insulator in MnBi8Te13.

Researchers can use magnetic topological materials to realize exotic forms of matter that are not seen in other types of material. Scientists believe that the phenomena these materials exhibit could help advance quantum technology and increase the energy efficiency of future electronic devices. Researchers believe that a topological insulator that is inherently ferromagnetic, rather than gaining its properties by adding small numbers of magnetic atoms, is ideal for studying novel topological behaviors. This is because no external magnetic field is needed to study the material’s properties. It also means the material’s magnetism is more uniformly distributed. However, scientists have previously faced challenges in creating this kind of material. This new material consists of layers of manganese, bismuth, and tellurium atoms. It could provide opportunities for exploring novel phases of matter and developing new technologies. It also helps researchers study basic scientific questions about quantum materials.

Exercise may be key to developing treatments for rare movement disorders

Spinal cerebellar ataxia 6 (SCA6) is an inherited neurological condition which has a debilitating impact on motor coordination. Affecting around 1 in 100,000 people, the rarity of SCA6 has seen it attract only limited attention from medical researchers. To date, there is no known cure and only limited treatment options exist.

Now, a team of McGill University researchers specializing in SCA6 and other forms of ataxia, have published findings that not only offer hope for SCA6 sufferers but may also open the way to developing treatments for other movement disorders.

Exercise in a pill

In mice affected by SCA6, the McGill team, led by biology professor Alanna Watt, found that exercise restored the health of cells in the cerebellum, the part of the brain implicated in SCA6 and other ataxias. The reason for the improvement, the researchers found, was that exercise increased levels of brain-derived neurotrophic factor (BDNF), a naturally occurring substance in the brain which supports the growth and development of nerve cells. Importantly for patients with a movement disorder, for whom exercise may not always be feasible, the team demonstrated that a drug that mimicked the action of BDNF could work just as well as exercise, if not better.

Brain Injury Model Created to Find New Medication

The experiments on the fish were conducted non-invasively, using a laser machine.
Photo credit: Danil Lomovskikh

Scientists from Russia and Taiwan (China) have developed and successfully tested a new model of traumatic brain injury (TBI) in zebradanio fish (Danio rerio). The method is based on irradiating the brains of adult individuals of these popular aquarium and laboratory fish with a unique laser system with precise aiming, which was specially developed by scientists. The application of this model allowed the researchers to simulate the TBI and identify molecular targets promising for the treatment of neurotrauma and its consequences. This paves the way for preclinical zebrafish testing of new neuroprotective medications.

The work was financially supported by the Russian Science Foundation (grant № 20-65-46006). An article describing the research was published in the highly rated scientific journal Pharmaceutics. The subject of the research was explained by Alan Kaluev, professor of the Russian Academy of Sciences, member of the European Academy, leading researcher of the Research Institute of Neuroscience and Medicine, professor of the St. Petersburg State University and Sirius Scientific-Technological University, leading researchers of the Ural Federal University and the Moscow Institute of Physics and Technology. Professor Kaluev is a leading scientist within the framework of research conducted at the Scientific Novosibirsk Research Institute of Neuroscience and Medicine (laboratory of Tamara Amstislavskaya and Maria Tikhonova).

The most common experimental models of brain injury in both rodents and zebrafish, such as mechanical blows to the head or needle piercing of the brain, involve penetrating brain tissue damage. However, these models do not correctly reproduce TBI. In the created model, due to the fact that the skin and skull of the used zebradanio species are transparent, it was possible to hit directly the brain, and non-invasively.

Data science reveals universal rules shaping cells’ power stations

Painted in the same style: scientists have shown that the same principles shape the evolution of chloroplasts (left), mitochondria (right), and other symbionts across life.
Photo credit: Iain Johnston and Sigrid Johnston-Røyrvik.

In the article, an international team of researchers, led by Professor Iain Johnston at the University of Bergen, explains how these rules determine why these organelles retain their own DNA instead of losing it to the host cells.

The research is part of a wider project funded by the European Research Council (ERC), and builds on findings the research group has previously published about mitochondria. Learn more about this in a previous Science article.

Same "rules" determine development

Mitochondria are compartments – so-called “organelles” -- in our cells that provide the chemical energy supply we need to move, think, and live. Chloroplasts are organelles in plants and algae that capture sunlight and perform photosynthesis. At a first glance, they might look worlds apart. But an international team of researchers, led by the University of Bergen, have used data science and computational biology to show that the same “rules” have shaped how both organelles – and more – have evolved throughout life’s history.

Decoding how bacteria talk with each other

Bacillus cereus, SEM image
Credit: Mogana Das Murtey and Patchamuthu Ramasamy, CC BY-SA 3.0

Bacteria, the smallest living organisms in the world, form communities where unified bodies of individuals live together, contribute a share of the property and share common interests.

The soil around a plant’s roots contains millions of organisms interacting constantly — too many busy players to study at once, despite the importance of understanding how microbes mingle.

In a study published in the journal mBio, researchers at the University of Wisconsin–Madison learned that a drastically scaled-down model of a microbial community makes it possible to observe some of the complex interactions. In doing so, they discovered a key player in microbial communication: the presence or absence of an antibiotic compound produced by one of the community members affected the behavior of the other two members.

Little is understood about how individual microbes interact with each other in communities, but that knowledge holds incredible promise.

For example, the bacteria Bacillus cereus can protect plants by producing an antibiotic that deters the pathogen that causes “damping off,” a disease that kills seedlings and is costly to farmers. But biocontrol agents like B. cereus are not always effective. Sometimes plants treated with B. cereus flourish, sometimes they don’t — and researchers are trying to understand why.

New wearable device measures the changing size of tumors below the skin

The FAST system measures tumor size regression and is a new way to test the efficacy of cancer drugs.
  Image credit: Alex Abramson, Bao Group, Stanford University

Electronically sensitive, skin-like membrane can measure changes in tumor size to the hundredth of a millimeter. It represents a new, faster, and more accurate approach to screen cancer drugs.

Engineers at Stanford University have created a small, autonomous device with a stretchable and flexible sensor that can be adhered to the skin to measure the changing size of tumors below. The non-invasive, battery-operated device is sensitive to one-hundredth of a millimeter (10 micrometers) and can beam results to a smartphone app wirelessly in real time with the press of a button.

In practical terms, the researchers say, their device – dubbed FAST for “Flexible Autonomous Sensor measuring Tumors” – represents a wholly new, fast, inexpensive, hands-free, and accurate way to test the efficacy of cancer drugs. On a grander scale, it could lead to promising new directions in cancer treatment. FAST is detailed in a paper published Sept. 16 in Science Advances.

Each year researchers test thousands of potential cancer drugs on mice with subcutaneous tumors. Few make it to human patients, and the process for finding new therapies is slow because technologies for measuring tumor regression from drug treatment take weeks to read out a response. The inherent biological variation of tumors, the shortcomings of existing measuring approaches, and the relatively small sample sizes make drug screenings difficult and labor-intensive.

20 years of AIRS Global Carbon Dioxide (CO₂) measurements

Data visualization of global carbon dioxide (CO₂) for the period September 2002-May 2022, showcasing data products from NASA's Aqua mission 

Visualizations by Helen-Nicole Kostis

This data visualization shows the global distribution and variation of the concentration of mid-tropospheric carbon dioxide observed by the Atmospheric Infrared Sounder (AIRS) on the NASA Aqua spacecraft over a 20-year timespan. One obvious feature that we see in the data is a continual increase in carbon dioxide with time, as seen in the shift in the color of the map from light yellow towards red as time progresses. Another feature is the seasonal variation of carbon dioxide in the northern hemisphere, which is governed by the growth cycle of plants. This can be seen as a pulsing in the colors, with a shift towards lighter colors starting in April/May each year and a shift towards red as the end of each growing season passes into winter. The seasonal cycle is more pronounced in the northern hemisphere than the southern hemisphere, since the majority of the land mass is in the north.

Higher risk of serious COVID-19 complications in children with immunodeficiency

Qiang Pan Hammarström, professor at Karolinska Institutet.
Photo credit: Erik Flyg.

Children with certain immunodeficiency diseases carry mutations in genes that regulate the body’s immune system against viral infections and they have a higher mortality rate due to COVID-19. This is according to a study by researchers from Karolinska Institutet, published in the Journal of Allergy and Clinical Immunology (PDF).

Most children infected with the SARS-CoV-2 coronavirus develop a mild illness or show no symptoms at all. But for a small percentage, serious complications may develop.

“Mortality is much higher among children with primary immunodeficiency diseases infected with SARS-CoV-2. Our results indicate that basic immunological examination and genetic analysis should be conducted in children with severe COVID-19 or multi-inflammatory syndrome (MIS-C). The clinicians will then be able to help these children with more precise therapies based on their genetic changes,” says Qiang Pan-Hammarström, professor at the Department of Biosciences and Nutrition, Karolinska Institutet, who led the study.

How the infection affects patients with primary immunodeficiency diseases, i.e. hereditary and congenital diseases of the immune system, is controversial. Even among these patients, some suffer from severe COVID-19 while others experience mild or no symptoms.

Improved Mineralized Material Can Restore Tooth Enamel

Scientists tested the effectiveness of the new enamel coating on real healthy teeth.
Photo credit: Danil Ilyukhin

Scientists have perfected hydroxyapatite, a material for mineralizing bones and teeth. By adding a complex of amino acids to hydroxyapatite, they were able to form a dental coating that replicates the composition and microstructure of natural enamel. Improved composition of the material repeats the features of the surface of the tooth at the molecular and structural level, and in terms of strength surpasses the natural tissue. The new method of dental restoration can be used to reduce the sensitivity of teeth in case of abrasion of enamel or to restore it after erosion or improper diet. The study and experimental results are published in Results in Engineering.

"Tooth enamel has a protective function, but unfortunately, its integrity can be destroyed by, for example, abrasion, erosion or microfractures. If the surface of the tissue is not repaired in time, the enamel lesion will affect the dentin and then the pulp of the tooth. Therefore, it is necessary to restore the enamel surface to a healthy level or build up additional layers on the surface if it has become very thin. We have created a biomimetic (i.e., mimicking natural) mineralized layer whose nanocrystals replicate the ordering of apatite nanocrystals of tooth enamel. We also found out that the designed layer of hydroxyapatite has increased nanohardness that exceeds that of native enamel," says Pavel Seredin, Leading Specialist of Research and Education Center "Nanomaterials and Nanotechnologies", Ural Federal University, Head of the Department of Solid State Physics and Nanostructures at Voronezh State University.

Mexican mangroves have been capturing carbon for 5,000 years

Unusual forests on stilts mitigate climate change
Credit: Ramiro Arcos Aguilar/UCSD

Researchers have identified a new reason to protect mangrove forests: they’ve been quietly keeping carbon out of Earth’s atmosphere for the past 5,000 years.

Mangroves thrive in conditions most plants cannot tolerate, like salty coastal waters. Some species have air-conducting, vertical roots that act like snorkels when tides are high, giving the appearance of trees floating on stilts.

A UC Riverside and UC San Diego-led research team set out to understand how marine mangroves off the coast of La Paz, Mexico, absorb and release elements like nitrogen and carbon, processes called biogeochemical cycling.

As these processes are largely driven by microbes, the team also wanted to learn which bacteria and fungi are thriving there.

The team expected that carbon would be found in the layer of peat beneath the forest, but they did not expect that carbon to be 5,000 years old. This result, along with a description of the microbes they identified, is now published in the journal Marine Ecology Progress Series.