Astro­physics: Star-child­hood shapes stel­lar evo­lu­tion

Tarantula Nebula: In this famous star-forming region in our neighboring galaxy, the Large Magellanic Cloud, many young stars are still in their molecular clouds, pictured by James Webb Space Telescope.
Hi-Res Zoomable Image
Credits: NASA, ESA, CSA, STScI, Webb ERO Production Team

In classical models of stellar evolution, so far little importance has been attached to the early evolution of stars. Thomas Steindl from the Institute of Astro- and Particle Physics at the University of Innsbruck now shows for the first time that the biography of stars is indeed shaped by their early stage. The study was published in Nature Communications.

From babies to teenagers: stars in their "young years" are a major challenge for science. The process of star formation is particularly complex and difficult to map in theoretical models. One of the few ways to learn more about the formation, structure or age of stars is to observe their oscillations. "Comparable to the exploration of the Earth's interior with the help of seismology, we can also make statements about their internal structure and thus also about the age of stars based on their oscillations" says Konstanze Zwintz. The astronomer is regarded as a pioneer in the young field of asteroseismology and heads the research group "Stellar Evolution and Asteroseismology" at the Institute for Astro- and Particle Physics at the University of Innsbruck. The study of stellar oscillations has evolved significantly in recent years because the possibilities for precise observation through telescopes in space such as TESS, Kepler, and James Webb have improved on many levels. These advances are now also shedding new light on decades-old theories of stellar evolution.

Diabetes: when circadian lipid rhythms go wrong

Circadian clocks in human pancreatic islets control the lipid membrane fluidity. Right, human pancreatic islet cells with compromised clocks bear decreased membrane lipid fluidity, as compared to the islet cells with functional clocks (left)
Resized Image using AI by SFLORG
Credit: 2022. Petrenko et al. (2022) Type 2 diabetes disrupts circadian orchestration of lipid metabolism and membrane fluidity in human pancreatic islets. PLoS Biol 20(8): e3001725.

Like all living beings, human physiological processes are influenced by circadian rhythms. The disruption of our internal clocks due to an increasingly unbalanced lifestyle is directly linked to the explosion in cases of type 2 diabetes. By what mechanism? A team from the University of Geneva (UNIGE) and the University Hospitals of Geneva (HUG), in Switzerland, is lifting part of the veil: this disturbance disrupts the metabolism of lipids in the cells that secrete glucose-regulating hormones. Sphingolipids and phospholipids, lipids located on the cell membrane, seem to be particularly affected. This change in lipid profiles then leads to rigidity of the membrane of these cells. These results, to be read in the journal PLOS Biology, provide further evidence of the importance of circadian rhythms in metabolic disorders.

Lipids have a variety of cellular functions. As one of the main components of cell membranes, they are involved in the signaling pathways through which cells communicate with each other and with their environment. “We have known for some time that the disruption of circadian clocks was closely linked to metabolic diseases, such as type 2 diabetes, where the body is no longer able to regulate blood sugar levels effectively,” explains Charna Dibner, a professor in the Departments of Surgery and of Cellular Physiology and Metabolism, as well as in the Diabetes Centre of the UNIGE Faculty of Medicine and the HUG, who led this research. “It is also established that lipids play a significant role in metabolic disorders. But the impact of circadian rhythms on lipid functions remained unknown.”

New Way to Obtain High-Productivity Proton Conductors Found

Natalya Tarasova works on the creation of new proton conductors.
Photo credit: Ilya Safarov.

Scientists from the Ural Federal University and the Institute of High Temperature Electrochemistry of the Ural Branch of the Russian Academy of Sciences carried out the first demonstration of donor and acceptor doping of perovskite with a barium-lanthanum indite block-layer structure. The fundamental possibility of such a method to significantly improve the conducting properties of the material was shown. The work opens a new way to the creation of solid oxide fuel cell electrolytes. An article describing the research and its results was published in Ceramics International.

One of the goals of global materials science is to obtain the highest possible electrical conductivity of electrolytes for their further use in solid oxide fuel cells. For this purpose, doping is the replacement of part of the atoms in the starting materials by atoms of another chemical element (acceptor doping is replacement by atoms with a lower valence, donor doping is replacement by atoms with a higher valence).

"We used barium-lanthanum iodate as the initial structure and during our studies we substituted some indium atoms for titanium (donor doping) and some lanthanum atoms for calcium (acceptor doping) in it. When acceptor doping, oxygen defects - oxygen vacancies - appeared in the crystal lattice of the initial material. This can ensure the transfer of protons - positively charged hydrogen ions - along the crystal lattice. They get into the structure of layered perovskite from humidified air at 300-500°C. The more oxygen defects and, consequently, the greater the concentration of protons in the perovskite crystal lattice and their mobility, i.e. speed, the higher the values of the electrical conductivity of the material," explains Natalya Tarasova, Professor of the Department of Physical Chemistry and Leading Researcher of the Institute of Hydrogen Energy at UrFU.

The magneto-optic modulator

Electricity flowing through a metal coil generates electric (purple) and magnetic (faint green) fields. This changes the properties of the substrate, which tunes the resonance ring (red) to different frequencies. The whole setup enables the scientists to convert a continuous beam of light (red on left) into pulses that can carry data through a fiber-optic cable. 
Photo Credit: Brian Long

Many state-of-the-art technologies work at incredibly low temperatures. Superconducting microprocessors and quantum computers promise to revolutionize computation, but scientists need to keep them just above absolute zero (-459.67° Fahrenheit) to protect their delicate states. Still, ultra-cold components have to interface with room temperature systems, providing both a challenge and an opportunity for engineers.

An international team of scientists, led by UC Santa Barbara’s Paolo Pintus, has designed a device to help cryogenic computers talk with their fair-weather counterparts. The mechanism uses a magnetic field to convert data from electrical current to pulses of light. The light can then travel via fiber-optic cables, which can transmit more information than regular electrical cables while minimizing the heat that leaks into the cryogenic system. The team’s results appear in the journal Nature Electronics.

Even the smartest AI models don’t match human visual processing

The study employed novel visual stimuli called “Frankensteins
Source/Credit: York University

Deep convolutional neural networks (DCNNs) don’t see objects the way humans do – using configural shape perception – and that could be dangerous in real-world AI applications, says Professor James Elder, co-author of a York University study.

Published in the Cell Press journal iScience, Deep learning models fail to capture the configural nature of human shape perception is a collaborative study by Elder, who holds the York Research Chair in Human and Computer Vision and is Co-Director of York’s Centre for AI & Society, and Assistant Psychology Professor Nicholas Baker at Loyola College in Chicago, a former VISTA postdoctoral fellow at York.

The study employed novel visual stimuli called “Frankensteins” to explore how the human brain and DCNNs process holistic, configural object properties.

“Frankensteins are simply objects that have been taken apart and put back together the wrong way around,” says Elder. “As a result, they have all the right local features, but in the wrong places.”

The investigators found that while the human visual system is confused by Frankensteins, DCNNs are not – revealing an insensitivity to configural object properties.

In the sea anemone, the way you move matters

Sea anemones, it turns out, also benefit from maintaining an active lifestyle, particularly as they grow from ovoid-shaped swimming larvae to sedentary, tubular polyps. The tissue is visualized using actin-staining.
Credit: Ikmi group/EMBL and ALMF/EMBL

Researchers from EMBL’s Ikmi group employed an interdisciplinary approach to show how sea anemone ‘exercise’ changes their developing size and shape, uncovering an intimate relationship between behavior and body development.

As humans, we know that an active lifestyle gives us some control over our form. When we hit the pavement, track our steps, and head to the gym, we can develop muscle and reduce body fat. Our physical activity helps shape our physical figure. But what if we performed similar aerobics in our earliest forms?

Researchers at EMBL’s Ikmi group turned this question towards the sea anemone to understand how behavior impacts body shape during early development. Sea anemones, it turns out, also benefit from maintaining an active lifestyle, particularly as they grow from egg-shaped swimming larvae to sedentary, tubular polyps. This morphological transformation is a fundamental transition in the life history of many cnidarian species, including the immortal jellyfish and corals, the builders of our planet’s richest and most complex ecosystems.

During development, starlet sea anemone larvae (Nematostella) perform a specific pattern of gymnastic movements. Too much or too little muscle activity or a drastic change in the organization of their muscles can cause the sea anemone to deviate from its normal shape.

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.