Smilodon's saber teeth

Life-size reconstruction of three different species studied with their stress thermal maps at the three different angles for a right lower canine bite. The colder colors on the thermal maps of saber-toothed species indicate lower stress and higher force, especially when biting at larger angles.
Illustration Credit: Massimo Molinero

A team of researchers led by Narimane Chatar, doctoral student at EDDyLab at the University of Liège, tested the bite effectiveness of the Smilodon, an extinct species of carnivore close to current felines. Thanks to high precision 3D scans and simulation methods, the team has just revealed how these animals managed to bite despite the impressive length of their teeth. This study is the subject of a publication in the journal Proceedings of the Royal Society B

ancient carnivorous mammals have developed a wide range of skulls and teeth throughout their evolution. However, few of these developments have yet equaled those of the felidated saber-toothed emblematic Smilodon. Other groups of mammals, such as the now extinct nimravids, have also evolved into a similar morphology, with species with saber teeth but also much shorter canines, similar to those of lions, tigers, caracals, domestic cats, etc. that we know today. This phenomenon of the appearance of similar morphologies in different groups of organisms is known as convergent evolution; felines and nimravids being an astonishing example of convergence. As there are no modern animal equivalents with such saber-shaped teeth, the hunting method. Smilodon and other similar species remained obscure and the subject of heated debate. It was initially suggested that all saber-toothed species hunted in the same way, regardless of the length of their canines, a hypothesis which is today controversial. From then on, the question remained suspended ... How did this variety of "saber-toothed cats" hunt?

SARS-CoV-2 protein caught severing critical immunity pathway

This image shows the SARS-CoV-2 virus's main protease, Mpro, and two strands of a human protein, called NEMO. One NEMO strand (blue) has been cut by Mpro, and the other NEMO strand (red) is in the process of being cut by Mpro. Without NEMO, an immune system is slower to respond to increasing viral loads or new infections. Seeing how Mpro attacks NEMO at the molecular level could inspire new therapeutic approaches. 
Illustration Credit: Greg Stewart/SLAC National Accelerator Laboratory

Over the past two years, scientists have studied the SARS-CoV-2 virus in great detail, laying the foundation for developing COVID-19 vaccines and antiviral treatments. Now, for the first time, scientists at the Department of Energy’s SLAC National Accelerator Laboratory have seen one of the virus’s most critical interactions, which could help researchers develop more precise treatments.

The team caught the moment when a virus protein, called Mpro, cuts a protective protein, known as NEMO, in an infected person. Without NEMO, an immune system is slower to respond to increasing viral loads or new infections. Seeing how Mpro attacks NEMO at the molecular level could inspire new therapeutic approaches.

To see how Mpro cuts NEMO, researchers funneled powerful X-rays from SLAC’s Stanford Synchrotron Radiation Lightsource (SSRL) onto crystallized samples of the protein complex. The X-rays struck the protein samples, revealing what Mpro looks like when it dismantles NEMO’s primary function of helping our immune system communicate.

New findings on how to avert excessive weight loss from COVID-19

Professor Yihai Cao.
Photo Credit: Dr. Muyi Yang.

Losing too much weight when infected with COVID-19 has been linked to worse outcomes. Now, researchers at Karolinska Institutet have discovered that SARS-CoV-2 infection fuels blood vessel formation in fat tissues, thus revving up the body’s thermogenic metabolism. Blocking this process by using an existing drug curbed weight loss in mice and hamsters that were infected with the virus, according to the study published in the journal Nature Metabolism.

“Our study proposes a completely new concept for treating COVID-19 associated weight loss by targeting the blood vessels in the fat tissues,” says Yihai Cao, professor at the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, and the study’s corresponding author.

The researchers examined how different types of fat, including brown fat and visceral and subcutaneous white fat, reacted when exposed to SARS-CoV-2 and how it impacted weight in mice and hamsters. They found that the animals lost significant amounts of weight in four days and that this weight loss was preceded by the activation of brown fat and the browning of both types of white fat. These fat tissues also contained more microvessels and high levels of a signaling protein called vascular endothelial growth factor (VEGF), which promotes the growth of new blood vessels.

Neural Network Learned to Create a Molecular Dynamics Model of Liquid Gallium

The melt viscosity determines the choice of casting mode, ingot formation conditions and other parameters.
Photo Credit: Ilya Safarov

Scientists at the Institute of Metallurgy, Ural Branch of the Russian Academy of Sciences, and Ural Federal University have developed a method for theoretically high-precision determination of the viscosity of liquid metals using a trained artificial neural network. The method was successfully tested in the process of building the deep learning potential of the neural network on the example of liquid gallium. Scientists were able to significantly increase the spatiotemporal scale of the simulation. The results of molecular dynamics modeling of liquid gallium are particularly accurate. Previous calculations were notoriously inaccurate, especially in the low temperature range. An article describing the research was published in the journal Computational Materials Science.

"First, liquids are in principle difficult to be described theoretically. The reason, in our opinion, lies in the absence of a simple initial approximation for this class of systems (for example, the initial approximation for gases is the ideal gas model). Secondly, the atomistic calculation of viscosity requires processing of a large volume of statistical data and, at the same time, a large accuracy of description of the potential energy surface and forces acting on atoms. Direct calculations cannot achieve such an effect. Thirdly, gallium in the liquid state is difficult to describe theoretically, because, due to certain features, its structure differs from that of most other metals," explains Vladimir Filippov, Senior Researcher at the Department of Rare Metals and Nanomaterials at UrFU, research participant and co-author of the article.

Very fast, but not a supersonic

The computer model of the dinosaur tail used and a diplodocide
Image Credit: Simone Conti / Zachi Evenor

An international research team with the participation of the Department of Biology at the University of Hamburg has analyzed the mobility of dinosaur tails using computer models and methods from engineering. According to a study published in Scientific Reports, the researchers found that these tails could be moved more than 100 kilometers per hour. Unlike previously assumed, however, they did not reach supersonic speed.

Diplodocids were large herbivorous dinosaurs with long necks and long tails. In a previous study, it was believed that a hypothetical structure at the end of a diplodocid's tail, similar to the end of a whip, could move faster than the speed of sound (340 meters per second) and produce a supersonic bang.

To test this hypothesis, the international research team simulated the movements of the tail of diplodocids using a model based on five fossil diplodocid skeletons. The virtual tail model is over 12 meters long, would weigh 1,446 kilograms in real terms and consists of 82 cylinders, which are supposed to represent vertebrae and are attached to an immovable, virtual basin.

“Research was quite a challenge, because we had to tackle the problem with two methods, that are normally used in aerospace technology: multi-body simulation and the estimation of the resilience of the materials”, reports the first author of the study, Simone Conti from the Universidade NOVA de Lisboa and the Politecnico di Milano.

Corona vaccination also protects people infected with HIV

They represent the study team: Clara Bessen, Carlos Plaza Sirvent, Adriane Skaletz-Rorowski, Anja Potthoff and Agit Simsek (from left).
Photo Credit: RUB, Marquard

A study shows that booster vaccination is particularly useful.

HIV-infected people who receive antiretroviral therapy form antibodies against Sars-Cov-2 after the Corona vaccination with mRNA vaccines. However, your immune response to vaccination is less strong than that of healthy people. The difference is reduced by a third vaccination. These results were achieved by a study with a total of 91 participants, which was carried out by a research team led by Prof. Dr. Ingo Schmitz, head of the Molecular Immunology Department at the Ruhr University in Bochum. The researchers report in the journal Frontiers in Immunology.

Vaccination protection for acquired immunodeficiency

Studies have shown that Sars-Cov-2 vaccines protect otherwise healthy people well against a severe course of Covid-19. It has so far been unclear whether this will also be the case for people with acquired immune deficiency. The research team led by Ingo Schmitz and Dr. Anja Potthoff from the Walk in Ruhr (WIR) Center for Sexual Health and Medicine at the RUB University Hospital included 71 people in her study who are HIV positive and receive antiretroviral therapy. 20 HIV-negative control persons also participated. After the first, second and third vaccinations with the mRNA vaccine from Biontech / Pfizer, they examined the immune response of the participants.

Intricate ‘snowflakes’ created in liquid metal

A snowflake-like zinc crystal synthesized in liquid gallium by researchers at UNSW Sydney.
Image Credit: Dr Jianbo Tang

Researchers, including those from UNSW Sydney, have synthesized complex symmetrical zinc crystals in liquid gallium which can potentially be used in a range of catalysis applications.

It’s beginning to look a lot like Christmas at UNSW Sydney’s School of Chemical Engineering where researchers have grown crystals made of zinc that look like snowflakes - inside a liquid metal.

The team predominantly used zinc metal dissolved in liquid gallium as the solvent, creating distinctive structures that often resembled those of six-branched snowflake crystals.

Apart from their structural beauty, these liquid metal-grown crystals can enable future processes for making catalytic materials for producing hydrogen from organic fuels. The metallic crystals can also be specially formulated, during their synthesis and extraction, to make semiconductors for electronic and optical devices of computers, mobile phones and solar cells of the future.

Cities on asteroids? It could work—in theory

In what they deem a “wildly theoretical” paper, Rochester researchers imagine covering an asteroid in a flexible, mesh bag made of ultralight and high-strength carbon nanofibers as the key to creating human cities in space.
Illustration Credit: University of Rochester | Michael Osadciw

Rochester scientists use physics and engineering principles to show how asteroids could be future viable space habitats.

This past year, Jeff Bezos launched himself into space, while Elon Musk funded a space flight for a non-astronaut crew. Space collaborations between government and private entities, including Musk’s SpaceX and Bezos’s Blue Origin have become increasingly common. But with the recent emergence of the so-called “New Space” movement, aerospace companies are working to develop low-cost access to space for everyone, not only billionaires.

For a future beyond Earth, however, humans need places to accommodate homes, buildings, and other structures for millions of people to live and work.

Right now, space cities exist only in science fiction. But are space cities feasible in reality? And, if so, how?

According to new research from University of Rochester scientists, our future may lie in asteroids.

In what they deem a “wildly theoretical” paper published in the journal Frontiers in Astronomy and Space Sciences, the researchers, including Adam Frank, the Helen F. and Fred H. Gowen Professor of Physics and Astronomy, and Peter Miklavčič, a PhD candidate in mechanical engineering and the paper’s first author, outline a plan for creating large cities on asteroids.

Say Hello to the Toughest Material on Earth

Microscopy-generated images showing the path of a fracture and accompanying crystal structure deformation in the CrCoNi alloy at nanometer scale during stress testing at 20 kelvin (-424 F). The fracture is propagating from left to right.
Image Credit: Robert Ritchie/Berkeley Lab

Scientists have measured the highest toughness ever recorded, of any material, while investigating a metallic alloy made of chromium, cobalt, and nickel (CrCoNi). Not only is the metal extremely ductile – which, in materials science, means highly malleable – and impressively strong (meaning it resists permanent deformation), its strength and ductility improve as it gets colder. This runs counter to most other materials in existence.

The team, led by researchers from Lawrence Berkeley National Laboratory (Berkeley Lab) and Oak Ridge National Laboratory, published a study describing their record-breaking findings in Science. “When you design structural materials, you want them to be strong but also ductile and resistant to fracture,” said project co-lead Easo George, the Governor’s Chair for Advanced Alloy Theory and Development at ORNL and the University of Tennessee. “Typically, it’s a compromise between these properties. But this material is both, and instead of becoming brittle at low temperatures, it gets tougher.”

CrCoNi is a subset of a class of metals called high entropy alloys (HEAs). All the alloys in use today contain a high proportion of one element with lower amounts of additional elements added, but HEAs are made of an equal mix of each constituent element. These balanced atomic recipes appear to bestow some of these materials with an extraordinarily high combination of strength and ductility when stressed, which together make up what is termed “toughness.” HEAs have been a hot area of research since they were first developed about 20 years ago, but the technology required to push the materials to their limits in extreme tests was not available until recently.

Argentine ants will do anything for sugar, but they won’t do this

 An Argentine ant tending aphids, plant parasites that secrete a sugar-rich substance the ants consume.
 Photo Credit: UCLA/Noa Pinter-Wollman

It might seem like common sense that a starving animal is more likely to take dangerous risks to obtain food than one with a full belly. But new research from UCLA shows that groups of Argentine ants, who forage boldly when they’re well fed, exercise far more caution when they’ve been deprived of carbohydrates and the risks from competitors are high.

This counterintuitive foraging strategy might contribute to the success of these insects, known as Linepithema humile, an invasive species that displaces native ant populations in California and elsewhere and has become a significant agricultural pest, the researchers said.

Their findings, published in the journal Current Zoology, suggest that the unwillingness of Argentine ants to expose themselves to danger when weakened by hunger could possibly give them a competitive edge over other species by helping to preserve their colonies’ foraging capabilities.

“While not foraging may lead to a reduction in food stores when those stores are already low, foraging in a high-risk environment exposes the colony to potential loss of foragers,” said the study’s senior author, Noa Pinter-Wollman, a UCLA professor of ecology and evolutionary biology. “So reduced foraging could be interpreted as individual foragers not taking unnecessary risks.”