. Scientific Frontline

Wednesday, June 8, 2022

Earth Is Safe: Astronomers Conducted a "Space Exercise"

Today, the distance from Apophis to Earth is 0.88 astronomical units, or almost 132 million km.
Photo: Eyes on Asteroids / NASA

More than 100 astronomers from 18 countries conducted a "space exercise". They joined their efforts to simulate the approach to the Earth of a dangerous asteroid and to estimate the probability of collision. Employees of the Kourovka Astronomical Observatory of the UrFU also took part in the project: Eduard Kuznetsov, Dmitry Glamazda, Galina Kaiser, Aleksandr Perminov and Yulia Vibe. The study was led by experts from NASA and the International Asteroid Warning Network (IAWN). The results are published in the Planetary Science Journal.

The asteroid Apophis, which was approaching Earth from December 2020 to March 2021, was taken as a sample of the potential threat. According to the "exercises", all data on Apophis were "forgotten", and scientists had to detect the asteroid again, determine its coordinates, speed, trajectory and many other parameters, as well as estimate the probability of collision with the Earth, the strength (energy) of the hit, which can cause an asteroid like Apophis. By common efforts it was even possible to determine the general composition of the asteroid and the properties of its surface. It was crucial, however, to understand how far in advance scientists were able to detect and how quickly they could classify extraterrestrial bodies that could pose a danger to the Earth.

International team visualizes properties of plant cell walls at nanoscale

Scattering-type scanning near-field optical microscopy, a nondestructive technique in which the tip of the probe of a microscope scatters pulses of light to generate a picture of a sample, allowed the team to obtain insights into the composition of plant cell walls.
Credit: Ali Passian/ORNL, U.S. Dept. of Energy

To optimize biomaterials for reliable, cost-effective paper production, building construction, and biofuel development, researchers often study the structure of plant cells using techniques such as freezing plant samples or placing them in a vacuum. These methods provide valuable data but often cause permanent damage to the samples.

A team of physicists including Ali Passian, a research scientist at the Department of Energy’s Oak Ridge National Laboratory, and researchers from the French National Centre for Scientific Research, or CNRS, used state-of-the-art microscopy and spectroscopy methods to provide nondestructive alternatives. Using a technique called scattering-type scanning near-field optical microscopy, the team examined the composition of cell walls from young poplar trees without damaging the samples.

But the team still had other obstacles to overcome. Although plant cell walls are notoriously difficult to navigate due to the presence of complex polymers such as microfibrils — thin threads of biomass that Passian describes as a maze of intertwined spaghetti strings — the team reached a resolution better than 20 nanometers, or about a thousand times smaller than a strand of human hair. This detailed view allowed the researchers to detect optical properties of plant cell materials for the first time across regions large and small, even down to the width of a single microfibril. Their results were published in Communications Materials.

Gravity-defying spike waves rewrite the rule book

The ‘spike wave’ created in the FloWave circular wave tank
Credit: University of Oxford

Researchers studying wave breaking have found that axisymmetric ‘spike waves' can far exceed limits that were previously thought to dictate the maximum height of ocean waves.

In a new study on ocean wave breaking, researchers have demonstrated that the breaking behavior of axisymmetric ‘spike waves’ is quite different to the long-established theories on the breaking of traveling waves.

Travelling waves break when waves become so steep that the crest is no longer stable. This leads to a breakdown of wave motion and energy loss. As a result, the height of the wave is limited by the breaking process.

‘Much of our understanding of wave breaking is routed in theories developed and experiments carried out in two dimensions when waves are moving in one direction,’ explained lead author Dr Mark McAllister, Department of Engineering Science, University of Oxford. ‘However, wave breaking in the ocean is a three-dimensional process.’

On the road to the super-battery

Dr. Anatoliy Senyshyn mounts a sample to analyze neutrons at the structure powder diffractometer SPODI at the Heinz Maier-Leibnitz Zentrum.
Credit: Bernhard Ludewig, FRM II /TUM

A research team led by the Technical University of Munich (TUM) has taken an in-depth look at the internal workings of batteries during charging and discharging. Their findings may help optimize charging processes.

When an electric car is being charged, the charge indicator moves quickly at first, then much more slowly at the end. "It's like putting things into a closet: In the beginning it's easy, but finding available space gets more difficult as the closet fills up," says Dr. Anatoliy Senyshyn from the Technical University of Munich's Research Neutron Source Heinz Maier-Leibnitz (FRM II).

The internal structure of a battery both before and after the charging process is already known. Led by the Heinz Maier-Leibnitz Zentrum (MLZ) at TUM, a research team has now observed for the first time a battery's lithium distribution during the entire charging and discharging process with the materials science diffractometer STRESS-SPEC. They then verified the measurements using the high-resolution powder diffractometer SPODI.

Interpreting underwater symphonies

Dr Hari Vishnu has researched on underwater soundscapes from the tropical waters of Singapore to the icy Arctic.
Credit: National University of Singapore

“The ocean is far less explored than we think. In fact, we know less about the depths of Earth’s oceans than we know about the surface of the Moon or Mars!” says Dr Hari Vishnu, Senior Research Fellow at the Acoustic Research Laboratory under the NUS Tropical Marine Science Institute, who listens to underwater sounds to discover the immense world beneath the waves.

“I study the use of sound to sense and understand underwater environments such as the ocean. Sound travels longer distances under water than light, and tells us a lot about what is happening in the ocean. I use sound-based sensing for diverse applications such as assessing Singapore’s marine biodiversity and the presence of marine mammals like dolphins and dugongs, improving capabilities of sonars used in defense applications, and deep-sea resource assessment,” shared Dr Vishnu.

With an academic background in computer engineering, as well as electrical and electronic engineering, Dr Vishnu was drawn to this area of research by his desire to make an impact on the under-explored world of the oceans: “Life originated in the oceans that cover more than 70 percent of the Earth, yet I feel it is underappreciated how crucial oceans are in determining its climate and supporting human survival. So, during my PhD, I decided to jump into this broad domain of ocean engineering. I specialized in studying how to process ocean sounds to interpret them and learn more about the ocean.”

Earth’s magnetic poles not likely to flip

Credit: ESA/ATG medialab

The emergence of a mysterious area in the South Atlantic where the geomagnetic field strength is decreasing rapidly, has led to speculation that Earth is heading towards a magnetic polarity reversal. However, a new study that pieces together evidence stretching back 9,000 years, suggests that the current changes aren’t unique, and that a reversal may not be in the cards after all. The study is published in PNAS.

The Earth’s magnetic field acts as an invisible shield against the life-threatening environment in space, and solar winds that would otherwise sweep away the atmosphere. However, the magnetic field is not stable, and at irregular intervals at an average of every 200,000 years polarity reversals happen. This means that the magnetic North and South poles swap places.

During the past 180 years, Earth’s magnetic field strength has decreased by about 10 percent. Simultaneously, an area with an unusually weak magnetic field has grown in the South Atlantic off the coast of South America. This area, where satellites have malfunctioned several times due to exposure to highly charged particles from the sun, is called the South Atlantic Anomaly. These developments have led to speculation that we may be heading for a polarity reversal. However, the new study suggests this may not be the case

Tuesday, June 7, 2022

Colossal collisions linked to solar system science

In this composite image of Abell 2146, Chandra X-ray data (purple) shows hot gas, and Subaru Telescope optical data shows galaxies (red and white).
Credit: Chandra X-ray / NASA

A new study shows a deep connection between some of the largest, most energetic events in the universe and much smaller, weaker ones powered by our own Sun.

The results come from a long observation with NASA’s Chandra X-ray Observatory of Abell 2146, a pair of colliding galaxy clusters located about 2.8 billion light-years from Earth. The new study was led by Helen Russell from the School of Physics and Astronomy and has been published online by The Monthly Notices of the Royal Astronomical Society

Galaxy clusters contain hundreds of galaxies and huge amounts of hot gas and dark matter and are among the largest structures in the universe. Collisions between galaxy clusters release enormous amounts of energy unlike anything witnessed since the big bang and provide scientists with physics laboratories that are unavailable here on Earth.

The shock wave is about 1.6 million light-years long and is most easily seen in a version of the X-ray image that has been processed to emphasize sharp features. Also labeled are the central core of hot gas in cluster #2, and the tail of gas it has left behind. A second shock wave of similar size is seen behind the collision. Called an “upstream shock,” features like this arise from the complex interplay of stripped gas from the infalling cluster and the surrounding cluster gas. The brightest and most massive galaxy in each cluster is also labeled.

Making Robotic Assistive Walking More Natural

 


A team of graduate students in Caltech's Advanced Mechanical Bipedal Experimental Robotics Lab (AMBER), led by Professor Aaron Ames, Bren Professor of Mechanical and Civil Engineering and Control and Dynamical Systems, is developing a new method of generating gaits for robotic assistive devices, which aims to guarantee stability and achieve more natural locomotion for different users.

A paper published in IEEE Robotics and Automation Letters outlines the AMBER team's method and represents the first instance of combining hybrid zero dynamics (HZD)—a mathematical framework for generating stable locomotion—with a musculoskeletal model to control a robotic assistive device for walking. The musculoskeletal model is a computational tool to noninvasively measure the relationship between muscle force and joint contact force. HZD is currently used to create stable walking gaits for bipedal robots, and the muscle model represents how much a muscle stretches or contracts with a given joint configuration.

The team demonstrates its approach on a battery-operated, motorized prosthetic leg. The battery powers the motors, which turn the joints. The motor movement is dictated by the mathematical algorithm developed by the researchers.

To create this mathematical algorithm, the AMBER research team recorded the muscle activity of a person walking with a prosthesis that followed the desired motion generated with HZD alone. This was done using electromyography (EMG), in which one electrode is placed on the skin above a specific muscle. Then the team analyzed the EMG activity of a person walking with a prosthesis that followed the desired motion generated by HZD combined with the muscle models. The latter more closely resembles how a human walks without a prosthesis.

Locking Leukemia’s Cellular Escape Hatch

Kris Wood, PhD, associate professor of
Pharmacology and Cancer Biology
Leukemia starts in cells that would normally develop into different types of blood cells. About 61,000 people in the U.S. are diagnosed each year, and depending on the type of leukemia and the age of the patient, five-year survival rates vary between about 20-80%.

After losing a close friend to an aggressive form of leukemia, acute myeloid leukemia (AML), Kris Wood, PhD, associate professor of pharmacology and cancer biology, devoted his research to helping find better treatment options for people with leukemias and lymphomas. He and his colleagues have discovered a potential new drug therapy that is preparing to enter clinical trials.

A new class of drugs called nuclear exportin inhibitors has recently been approved for use to treat cancers. Nuclear exportins are proteins that shuttle other proteins out of the nucleus of a cell. These new drugs stop the shuttle from leaving the station.

“The idea is that if you treat cells with a drug that blocks a nuclear exportin,” Wood said, “its client proteins become trapped in the nucleus.” And while researchers don’t fully understand why this is therapeutic, it works. Wood and his team investigated the mechanisms behind it. Their results were published in Nature Cancer.

First, they treated AML cells with Selinexor, a nuclear exportin inhibitor. At the same time, they used CRISPR screens to knock out thousands of genes across the genome one at a time to identify genes that made the drug work either much better or much worse when knocked out.

Equine eye docs help horse regain sight

Willy was diagnosed with equine recurrent uveitis, a common but harmful complex autoimmune disease among horses. After treatment, Willy regained most of his vision and has a high quality of life.
Source: Provided to Cornell University

Willy, a 3-year-old quarter horse, has a goofy personality and loves to spend time with his many chicken friends at owner Mariah Kauffman’s home in Snyder County, Pennsylvania.

Soon after Willy joined their family, however, Kauffman noticed that every once in a while, his eyes would cloud over, then appear clear the next day. “He started bumping into things and getting cuts on his face,” Kauffman said. “He would run into the fence and spooked easily.”

That’s when she decided to call Willy’s veterinarian, Dr. Jacqueline Rapp of Susquehanna Valley Veterinary.

Rapp quickly referred Willy to the Cornell Equine Hospital for specialty care from Dr. Kelly Knickelbein, assistant clinical professor, alongside ophthalmology residents Dr. Irini Lamkin and Dr. Brittany Schlesener.

The Cornell team diagnosed him with equine recurrent uveitis (ERU), a common but harmful complex autoimmune disease among horses, with both genetic and environmental factors.

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