Shape-Memory Polymers

Ilya Starodumov as a member of an international team, is developing a technology for creating "smart" polymers.
Credit: Ilya Safarov

Biocompatible polymers based on a "smart" material poly (ε-caprolactone) that keeps its shape may appear in Russia. An international team of scientists from Russia, Israel, and Japan, including physicists from Ural Federal University, work on the technology of its creation. The research is supported by the Russian Foundation for Basic Research.

Polymeric materials based on poly (ε-caprolactone) are suitable for biomedical purposes: for surgery, cell engineering, regenerative medicine. Such material can be used to make devices for minimally invasive surgery (with minimal incisions), self-tightening surgical sutures, etc. A description of this material was published in The Journal of Physical Chemistry B.

"A special feature of polymers with shape memory is the ability to return to the original shape when the temperature changes. It looks like this: a polymer product with a certain "programmed" shape is made. Then this product is deformed in any manner, for example, stretched or curled, like surgical sutures. When heated to a certain temperature, the memory mechanism in the polymer is activated at the molecular level, and the product restores its original shape," says Ilya Starodumov, Head of the Laboratory of Multiphase Physico-Biological Environment Simulation at UrFU.

Could we eavesdrop on communications that pass through our solar system?

Communications across interstellar distances could take advantage of a star’s ability to focus and magnify communication signals through an effect called gravitational lensing. A signal from—or passing through—a relay probe would bend due to gravity as it passes by the star. The warped space around the object acts somewhat like a lens of a telescope, focusing and magnifying the light. A new study by researchers at Penn State investigated our solar system for communication signals that might be taking advantage of our own sun.
Credit: Dani Zemba / Penn State

Communications across the vastness of interstellar space could be enhanced by taking advantage of a star’s ability to focus and magnify communication signals. A team of graduate students at Penn State is looking for just these sorts of communication signals that might be taking advantage of our own sun if transmissions were passing through our solar system.

A paper describing the technique — explored as part of a graduate course at Penn State covering the Search for Extraterrestrial Intelligence (SETI) — has been accepted for publication in the Astronomical Journal and is available on the preprint server arXiv.

Massive objects like stars and black holes cause light to bend as it passes by due to the object’s gravitational pull, according to Einstein’s Theory of General Relativity. The warped space around the object acts somewhat like a lens of a telescope, focusing and magnifying the light — an effect called gravitational lensing.

Underwater cave fossil site gains state protections

A reconstruction of the South Australian cave site which has been heritage listed due to its abundance of megafauna fossils.
Image by Peter Schouten.

A team of researchers and cave divers have successfully lobbied for the protection of a unique fossil site in South Australia, which could pave the way for the future preservation of other important paleontological sites around Australia.

The underwater cave site known as the Green Waterhole in the Mount Gambier region contains the only known extensive underwater vertebrate fossil deposits in Australia, has been listed on the South Australia State Heritage Register.

The unique freshwater depositional environment has ensured the preservation of extinct species of megafauna such as marsupial lions, short-faced kangaroos, and carnivorous kangaroos, with several additional species new to science recovered and awaiting description.

How Omicron dodges the immune system

Meriem Bekliz, first author, with a plaque-reduction neutralization assay used to determine the neutralizing capacity of antibodies.
Credit: HUG-UNIGE.

By comparing the neutralization capacity induced by the different variants of SARS-CoV-2, a team from the UNIGE and the HUG reveals the exceptional capacity of Omicron to evade our immunity.

The current wave of COVID-19 highlights a particularly high risk of reinfection by the Omicron variant of SARS-CoV-2. Why is this? A team from the Centre for Emerging Viral Diseases of the University of Geneva (UNIGE) and of the Geneva University Hospital (HUG) analyzed the antibody neutralization capacity of 120 people infected with the original SARS-CoV-2 strain, or with one of its Alpha, Beta, Gamma, Delta, Zeta or Omicron (sub-variant BA.1) variants. And unlike its predecessors, Omicron appears to be able to evade the antibodies generated by all other variants. In vaccinated individuals, while the neutralization capacity is also reduced, it remains far superior to natural immunity alone. This could explain why Omicron is responsible for a net increase in vaccine break-through infections, but not in hospitalizations. These results can be read in the journal Nature Communications.

Study reveals why highly infectious cholera variant mysteriously died out

Water sample in test tube
Credit: Photo by Martin Lopez

A new study reveals why a highly infectious variant of the cholera bug, which caused large disease outbreaks in the early 1990s, did not cause the eighth cholera pandemic as feared – but instead unexpectedly disappeared.

The study analyzed samples of O139 Vibrio cholerae, a variant of the bacteria that causes cholera, and discovered significant changes in its genome over time that led to its unexpected decline.

These genetic changes resulted in a gradual loss of antimicrobial resistance (AMR), and a change in the types of toxin produced by the cholera bug. In combination, these changes are likely to account for O139’s failure to seed the eighth cholera pandemic.

The cholera bug is not currently monitored on a regular basis. Scientists say continuous monitoring of the genes underlying AMR and toxin production is key to keeping ahead of the cholera bug as it evolves. In particular, this will help to plan changes to vaccines and appropriate public health responses to prevent future cholera outbreaks.

The O139 variant of Vibrio cholerae was first detected in India in 1992. It quickly became dominant over the existing O1 variant and caused huge disease outbreaks in India and Southern Bangladesh.

Researchers expand understanding of vortex spread in superfluids

An illustration of a vortex tangle.
Credit: Wei Guo/FAMU-FSU College of Engineering

An international team of scientists featuring Florida State University researchers has developed a model that predicts the spread of vortices in so-called superfluids, work that provides new insight into the physics that govern turbulence in quantum fluid systems such as superfluid neutron stars.

In a paper published in Physical Review Letters, the researchers created a model that describes the spread and speed of tornado-like vortex tubes in superfluids. Vortex tubes are a key ingredient of turbulence, which is widely studied in classical physics. The motion of vortex tubes is relevant in a wide range of scenarios, such as the formation of hurricanes, the airborne transmission of viruses and the chemical mixing in star formation. But it is poorly understood in quantum fluids.

This work expands on a previous study that reported experimental results obtained in superfluid helium-4 within a narrow temperature range. Superfluids are liquids that can flow without resistance, and therefore without a loss of kinetic energy. When they are stirred, they form vortices that rotate indefinitely.

“By validating this model and showing that it describes the movement of vortices at a wide range of temperatures, we are confirming a universal rule for this phenomenon,” said Wei Guo, an associate professor of mechanical engineering at the FAMU-FSU College of Engineering. “This discovery may aid the development of advanced theoretical models of quantum fluid turbulence.”

COVID-19 virus spike protein flexibility improved by human cell's own modifications

University of Illinois researchers created atomic-level models of the spike protein that plays a key role in COVID-19 infection and immunity, revealing how the protein bends and moves as it seeks to engage receptors. 
Credit: Tianle Chen

When the coronavirus causing COVID-19 infects human cells, the cell’s protein-processing machinery makes modifications to the spike protein that render it more flexible and mobile, which could increase its ability to infect other cells and to evade antibodies, a new study from the University of Illinois Urbana-Champaign found.

The researchers created an atomic-level computational model of the spike protein and ran multiple simulations to examine the protein’s dynamics and how the cell’s modifications affected those dynamics. This is the first study to present such a detailed picture of the protein that plays a key role in COVID-19 infection and immunity, the researchers said.

Biochemistry professor Emad Tajkhorshid, postdoctoral researcher Karan Kapoor and graduate student Tianle Chen published their findings in the journal PNAS.

“The dynamics of a spike are very important – how much it moves and how flexible it is to search for and bind to receptors on the host cell,” said Tajkhorshid, who also is a member of the Beckman Institute for Advanced Science and Technology. “In order to have a realistic representation, you have to look at the protein at the atomic level. We hope that the results of our simulations can be used for developing new treatments. Instead of using one static structure of the protein to search for drug-binding pockets, we want to reproduce its movements and use all of the relevant shapes it adopts to provide a more complete platform for screening drug candidates instead of just one structure.”

Why natural gas is not a bridge technology

The expansion of the natural gas infrastructure poses a risk to the energy transition, since natural gas is not a bridge technology towards a 100 percent renewable energy system within the meaning of the Paris climate agreement. This is the result of a study by an interdisciplinary German research team. July 2022 in the journal Nature Energy. The researchers examine the natural gas question from five perspectives and provide the gas with a similarly poor climate balance sheet as coal or oil. They recommend politics and science to revise the current assumptions about natural gas.

The study was led by Prof. Dr. Claudia Kemfert from the German Institute for Economic Research (DIW) and the Leuphana University of Lüneburg in collaboration with Franziska Hoffart from the Ruhr University Bochum, Fabian Präger from the Technical University of Berlin and Isabell Braunger and Hanna Brauers from the European University Flensburg.

Energy crisis is only one side of the problem

In the wake of the Russian war of aggression, the government in Germany faces the challenge of reducing Russia's energy dependency and continuing to ensure an affordable and secure energy supply that is in line with climate targets. Efforts are currently underway to balance Russian natural gas, the delivery of which is throttled and unsafe, by building new gas trading relationships and new infrastructure. Claudia Kemfert, head of the study, explains: “Fossil natural gas is neither clean nor safe. The too long adherence to fossil natural gas has led Germany into an energy crisis, from which now only decisive action for consistent decarbonization can lead to a full supply of renewable energies”.

Astronomers Identified the Nature of Instability in the Accretion Disk of the Galaxy NGC 4258

The galaxy NGC 4258 is 22.8 million light-years from Earth.
Photo Credit: NASA

An international group of researchers, including Andrey Sobolev, a leading researcher at the Kourovka Astronomical Observatory of the Ural Federal University, for the first time examined the details of the distribution of maser emissions in the accretion It was found that in this disk acts magneto-rotational instability. Scientists reported the discovery in the journal Nature Astronomy.

"The discovery of a disk around this galaxy was reported by Miyoshi and Greenhill back in 1995 in articles in Nature and in The Astrophysical Journal. That was the first time we knew there was a disk. But now, with the RadioAstron's ultra-high angular resolution, we have been able to ascertain for the first time the details of the distribution of the maser emission spots. The regularity in their maser locations is explained by the fact that there is a magneto-rotational instability in the accretion disk," says Andrey Sobolev.

The instabilities determine the evolution of disks. We can use them to know whether the disk is stationary or whether everything in it is changing rather rapidly. In other words, the instabilities help determine the physical status or physical state of the disk: how it is formed, what happens in it, and predict whether it will change over time. Therefore, to understand the processes that occur in the accretion disk, scientists need to understand what instabilities are operating there, and the detection of the magneto-rotational instability is extremely important. At the same time, scientists are not going to put an end to the research of the unique object around the supermassive black hole. According to Sobolev, now it is the turn of theorists to explain the unique data obtained at the cosmic interferometer - the largest device created by mankind. This interferometer was created as part of the RadioAstron project, in which Russian scientists play a leading role.

Gut bacteria potential key to IBD and colon cancer prevention

Jakob Begun  ATH - Associate Professor
Mater Research Institute-UQ Faculty of Medicine
Source: University of Queensland

Researchers have isolated five strains of gut bacteria that could pave the way for new inflammatory bowel disease treatments and potentially help prevent some forms of bowel cancer.

The study by University of Queensland and Mater researchers identified gut bacterial strains that suppress inappropriate gut inflammation and debilitating inflammatory bowel disease (IBD) symptoms.

IBD is a chronic condition characterized by relapsing gut inflammation believed to be caused by an abnormal gut bacterial composition which produces an immune response in genetically susceptible people resulting in severe symptoms.

University of Queensland researcher and Inflammatory Bowel Disease Research Group Leader, Associate Professor Jake Begun, said his team isolated bacteria found in the healthy gut and identified several species that produced a range of anti-inflammatory substances.

“While the gut microbiome is made up of trillions of bacteria that have co-evolved with humans over time, our lab tests identified five strains that were able to suppress inflammation in blood and tissue samples from IBD patients,” Dr Begun said.

“Furthermore, one of these healthy gut bacterial strains produced anti-inflammatory substances that were able to reduce disease severity in a pre-clinical model by inhibiting one of the master molecular regulators of inflammation called NF-kB, without causing any side-effects.”

Mater Research and UQ PhD candidate Rabina Giri said the research found good bacterial strains inhibited the pro-inflammatory enzyme NF-kB by about half.