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Comment by Dr. Krishna Kumari Challa on April 28, 2023 at 9:40am

Newly observed effect makes atoms transparent to certain frequencies of light

A newly discovered phenomenon dubbed "collectively induced transparency" (CIT) causes groups of atoms to abruptly stop reflecting light at specific frequencies.

CIT was discovered by confining ytterbium atoms inside an optical cavity —essentially, a tiny box for light—and blasting them with a laser. Although the laser's light will bounce off the atoms up to a point, as the frequency of the light is adjusted, a transparency window appears in which the light simply passes through the cavity unimpeded.

An analysis of the transparency window points to it being the result of interactions in the cavity between groups of atoms and light. This phenomenon is akin to destructive interference, in which waves from two or more sources can cancel one another out. The groups of atoms continually absorb and re-emit light, which generally results in the reflection of the laser's light. However, at the CIT frequency, there is a balance created by the re-emitted light from each of the atoms in a group, resulting in a drop in reflection.

An ensemble of atoms strongly coupled to the same optical field can lead to unexpected results.

Through conventional quantum optics measurement techniques, researchers found that their system had reached an unexplored regime, revealing new physics.

Besides the transparency phenomenon, the researchers also observed that the collection of atoms can absorb and emit light from the laser either much faster or much slower compared to a single atom depending on the intensity of the laser. These processes, called superradiance and subradiance, and their underlying physics are still not understood properly because of the large number of interacting quantum particles.

 Mi Lei et al, Many-body cavity quantum electrodynamics with driven inhomogeneous emitters, Nature (2023). DOI: 10.1038/s41586-023-05884-1

Comment by Dr. Krishna Kumari Challa on April 27, 2023 at 9:19am

Over the course of two field seasons, in 2019 and 2020, the study authors scoured the Changbaishan region for rivers and streams. They collected water samples from around two dozen sites and used radiocarbon dating to estimate the amount of "deep carbon," meaning carbon from the depths of Earth, that had seeped into the water. They compared deep carbon estimates to estimates of carbon incorporated into minerals through silicate weathering.

The researchers found that the Changbaishan region is a small net carbon source. Every year, the region releases at least 600 more tons of carbon than it incorporates—about the amount that 41 average Americans put into the atmosphere on an annual basis. That seems small, but over geological timescales, the impact could be significant.

The Changbaishan volcanic region is just one of many around the world, the researchers point out. Future work should examine wider areas to gain a full understanding of how volcanoes contribute to Earth's carbon cycle.

More information: Jun Zhong et al, Assessing the Deep Carbon Release in an Active Volcanic Field Using Hydrochemistry, δ 13 C DIC and Δ 14 C DIC, Journal of Geophysical Research: Biogeosciences (2023). DOI: 10.1029/2023JG007435

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Comment by Dr. Krishna Kumari Challa on April 27, 2023 at 9:18am

Do volcanoes add more carbon than they take away?

In a new study published in the Journal of Geophysical Research: Biogeosciences, researchers discovered that a volcano in northeast China emits a small net amount of carbon each year. Over geological timescales, that could have a significant impact on our planet's carbon cycle.

Volcanic areas continue to emit carbon dioxide long after eruptions are over. Conversely, atmospheric carbon dioxide (CO₂) is constantly locked away into minerals on Earth's surface through a process called silicate weathering. Whether volcanoes release more CO₂ through degassing or capture more CO₂ through silicate weathering is an open question.

The authors of the new study investigated whether the Changbaishan volcanic area in northeast China is a net source or sink of atmospheric carbon. The region has been active for at least 2.7 million years, but it has not erupted since 1903, making the area a prime spot for analyzing long-term carbon leakage.

Part 1

Comment by Dr. Krishna Kumari Challa on April 27, 2023 at 8:32am

Astronomers solve the 60-year mystery of quasars, the most powerful objects in the universe

Scientists have unlocked one of the biggest mysteries of quasars—the brightest, most powerful objects in the universe—by discovering that they are ignited by galaxies colliding.

First discovered 60 years ago, quasars can shine as brightly as a trillion stars packed into a volume the size of our solar system. In the decades since they were first observed, what could trigger such powerful activity has remained a mystery. New work by scientists has now revealed that it is a consequence of galaxies crashing together.

The collisions were discovered when researchers, using deep imaging observations from the Isaac Newton Telescope in La Palma, observed the presence of distorted structures in the outer regions of the galaxies that are home to quasars.

Most galaxies have supermassive black holes at their centers. They also contain substantial amounts of gas—but most of the time this gas is orbiting at large distances from the galaxy centers, out of reach of the black holes. Collisions between galaxies drive the gas towards the black hole at the galaxy center; just before the gas is consumed by the black hole, it releases extraordinary amounts of energy in the form of radiation, resulting in the characteristic quasar brilliance.

The ignition of a quasar can have dramatic consequences for entire galaxies—it can drive the rest of the gas out of the galaxy, which prevents it from forming new stars for billions of years into the future.

This is the first time that a sample of quasars of this size has been imaged with this level of sensitivity. By comparing observations of 48 quasars and their host galaxies with images of over 100 non-quasar galaxies, researchers concluded that galaxies hosting quasars are approximately three times as likely to be interacting or colliding with other galaxies.

J C S Pierce et al, Galaxy interactions are the dominant trigger for local type 2 quasars, Monthly Notices of the Royal Astronomical Society (2023). DOI: 10.1093/mnras/stad455

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 12:08pm

Earpiece that speeds up recovery after a stroke

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 11:40am

 How NASA is planning to protect Earth from asteroids and comets

NASA just released a new planetary defense strategy and action plan, describing its efforts to find and identify potentially hazardous objects to provide an advanced warning, and then even push them off an impact trajectory.

This 10-year strategy looks to advance efforts to protect the Earth from a devastating encounter with a Near Earth asteroid or comet.

The 46-page "NASA Planetary Defense Strategy and Action Plan" (pdf document) was released on April 18, 2023 and follows another document that was put out on April 3 by the White House Office of Science and Technology Policy, "National Preparedness Strategy and Action Plan for Near-Earth Object Hazards and Planetary Defense" (pdf document).

Each of the reports focuses on enhancing the detection, characterization and responses to impact threats as well as improving international cooperation for coordinating strategies among government agencies.

NASA wants to focus on six key areas for planetary defense over the next decade:

• Improving NEO survey, detection, and characterization efforts to work toward a completed catalog of all NEOs that might pose an impact hazard to Earth
• Developing and demonstrating NEO mitigation technologies similar to the agency's Double Asteroid Redirection Test (DART) mission, the world's first planetary defense test mission, which successfully demonstrated one method of asteroid deflection using a kinetic impactor spacecraft
• Fostering international collaboration related to NEO surveying and mitigation to leverage international capabilities
• Strengthening interagency coordination between NASA and other U.S. government agencies to enhance and streamline U.S. government NEO preparedness and response planning
• Review the agency's internal planning to maximize the benefits obtained from limited resources
• Better integrate messaging regarding planetary defense work with the agency's strategic communications

Each of the strategy objectives are defined into short-term, medium-term, long-term, and ongoing timelines with the goal of meeting all objectives within the next 10 years.

https://www.nasa.gov/feature/nasa-releases-agency-strategy-for-plan...

https://www.universetoday.com/161058/heres-how-nasa-is-planning-to-...

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 10:53am

How to land on a planet safely using a computational model

Understanding the interaction between the rocket plume and the surface is important for the safety and success of space missions in terms of contamination and erosion, landing accuracy, planetary protection, and engineering design, as well as for scientific understanding and future exploration.

When a lander descends toward the moon—or a rocky planet, asteroid, or comet—the exhaust plume of the rocket interacts with the surface, causing erosion and kicking up regolith particles. The resulting blanket of dusty debris can create a dangerous brownout effect, limiting visibility and potentially damaging the spacecraft or nearby equipment.

Researchers developed a model to describe the interaction between a rocket plume and the surface of a planetary body in near-vacuum conditions. The results can be used to evaluate the safety and feasibility of a proposed landing site and to optimize the design of spacecraft and rocket engines for planetary landings.

The computational framework takes in information about the rocket, its engines, and the surface composition and topography, as well as the atmospheric conditions and gravitational forces at the landing site.

By considering the interaction of the gas with solid particles as a system of equations, the simulation estimates the shape and size of the plume, the temperature and pressure of the plume and surface, and the amount of material eroded or displaced. It does so in a way that is more computationally efficient than previous methods.

In the model, small regolith particles reached high altitudes and caused severe brownout effects during ascent and descent. In contrast, larger particles with increased bed height led to a more favorable brownout status.

The insights gained from this study of the effects of different parameters on plume-surface interaction can inform the development of more effective and efficient landing technologies.

The researchers plan to improve the capabilities of the framework to include more complex physics, such as chemical reactions and solid particle collisions. They think the model can be applied to other physics scenarios including needle-free drug delivery systems.

Omid Ejtehadi et al, Full continuum approach for simulating plume-surface interaction in planetary landings, Physics of Fluids (2023). DOI: 10.1063/5.0143398

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 9:21am

The ongoing research aligns with the mission  where chemists are trying to discover the chemical "languages" of micro-organisms. Microbes use chemicals to communicate with each other, and then they use other chemicals to cooperate with or compete with each other. The researchers are applying chemical tools like

mass spectrometry and nuclear magnetic resonance spectroscopy  to decipher which molecules trigger cooperative and competitive responses in microbes.

Ultimately, they hope to use this knowledge to devise new approaches to defeat pathogens and promote the microbiomes that help humans.

 Núria Ros-Rocher et al, Chemical factors induce aggregative multicellularity in a close unicellular relative of animals, Proceedings of the National Academy of Sciences (2023). DOI: 10.1073/pnas.2216668120

Part 2

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 9:18am

Earliest animal likely used chemical signaling to evolve into multicellular organism

The earliest animal likely used chemical signaling to evolve from a single cell to a multicellular organism, according to a study by scientists. The findings provide new information about how one of the biggest transitions in the history of life on Earth likely occurred.

The general view is that animals evolved from a unicellular organism, and this research helps explain how that may have happened and how those cells chose whether to be together or on their own.

The study focused on one of the closest living relatives of animals, Capsaspora owczarzaki, which lives in snails. Capsaspora can form multicellular aggregates—cells that cluster together and adhere to each other—in a way that is similar to sponges or hydra.

To conduct their study, researchers systematically added and removed components of a liquid growth media to Capsaspora to determine which components regulated the cells adhering together. They discovered that calcium ions and lipids spurred multicellular aggregation. They also found that the process was reversible, and that when lipoproteins decreased, the cells separated.

The transition from being a single cell to a multicellular organism is a really big step. We now have a better understanding of how the ancestors of animals could have made that change using chemical cues.

Researchers are working on additional studies involving Capsaspora. The snail that Capsaspora resides in transmits a parasitic disease, and Capsaspora can kill the worm that causes the disease. If researchers can determine how the organism does that, there could be future medical applications.

Part 1

Comment by Dr. Krishna Kumari Challa on April 26, 2023 at 8:50am

For this paper, the researchers modified those particles by adding a chemical group that would react with a tag placed on the second component in the system, which they call the crosslinker. Those crosslinkers, made of either PEG or PEG-PLGA, bind to the targeting particles that have accumulated at a wound site and form clumps that mimic blood clots. 

The idea is that with both of these components circulating inside the bloodstream, if there is a wound site, the targeting component will start accumulating at the wound site and also bind the crosslinker. When both components are at high concentration, you get more cross-linking, and they begin forming that glue and helping the clotting process.

To test the system, the researchers used a mouse model of internal injury. They found that after being injected into the body, the two-component system was highly effective at stopping bleeding, and it worked about twice as well as the targeting particle on its own.

Another important advantage of the clots is that they don't degrade as fast as naturally occurring clots do. When patients lose a lot of blood, they are usually given saline intravenously to keep up their blood pressure, but this saline also dilutes the existing platelets and fibrinogen, leading to weaker clots and faster degradation. However, the artificial clots are not as susceptible to this kind of degradation, the researchers found.

The researchers also found that their nanoparticles did not induce any significant immune reaction in the mice compared to a glucose control. They now plan to test the system in a larger animal model.

Celestine Hong et al, Engineering a Two‐Component Hemostat for the Treatment of Internal Bleeding through Wound‐Targeted Crosslinking, Advanced Healthcare Materials (2023). DOI: 10.1002/adhm.202202756

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