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Comment by Dr. Krishna Kumari Challa on August 26, 2020 at 5:32am

Ancient star explosions revealed in the deep sea

A mystery surrounding the space around our solar system is unfolding thanks to evidence of supernovae found in deep-sea sediments.

A new study  shows the Earth has been traveling for the last 33,000 years through a cloud of faintly radioactive dust.

These clouds could be remnants of previous supernova explosions, a powerful and super bright explosion of a star.

The researchers searched through several deep-sea sediments from two different locations that date back 33,000 years using the extreme sensitivity of HIAF's mass spectrometer. They found clear traces of the isotope iron-60, which is formed when stars die in supernova explosions.

Iron-60 is radioactive and completely decays away within 15 million years, which means any iron-60 found on the earth must have been formed much later than the rest of the 4.6-billion-year old earth and arrived here from nearby supernovae before settling on the ocean floor.

found traces of iron-60 at about 2.6 million years ago, and possibly another at around 6 million years ago, suggesting earth had traveled through fallout clouds from nearby supernovae.

For the last few thousand years the solar system has been moving through a denser cloud of gas and dust, known as the local interstellar cloud, (LIC), whose origins are unclear. If this cloud had originated during the past few million years from a supernova, it would contain iron-60, and so the team decided to search more recent sediment to find out.

Sure enough, there was iron-60 in the sediment at extremely low levels—equating to radioactivity levels in space far below the Earth's natural background levels—and the distribution of the iron-60 matched earth's recent travel through the local interstellar cloud. But the iron-60 extended further back and was spread throughout the entire 33,000 year measurement period.

The lack of correlation with the solar system's time in the current local interstellar cloud seems to pose more questions than it answers. Firstly, if the cloud was not formed by a supernova, where did it come from? And secondly, why is there iron-60 so evenly spread throughout space?

There are recent papers that suggest iron-60 trapped in dust particles might bounce around in the interstellar medium.

So the iron-60 could originate from even older supernovae explosions, and what we measure is some kind of echo. More data is required to resolve these details.

A. Wallner et al. 60Fe deposition during the late Pleistocene and the Holocene echoes past supernova activity, Proceedings of the National Academy of Sciences (2020). DOI: 10.1073/pnas.1916769117

https://phys.org/news/2020-08-ancient-star-explosions-revealed-deep...

Comment by Dr. Krishna Kumari Challa on August 26, 2020 at 5:27am

Galactic bar paradox resolved in cosmic dance

New light has been shed on a mysterious and long-standing conundrum at the very heart of our galaxy. The new work offers a potential solution to the so-called "Galactic bar paradox," whereby different observations produce contradictory estimates of the motion of the central regions of the Milky Way.

The majority of spiral galaxies, like our home the Milky Way, host a large bar-like structure of stars in their center. Knowledge of the true bar size and rotational speed is crucial for understanding how galaxies form and evolve, as well as how they form similar bars throughout the universe.

However our galaxy's bar size and rotational speed have been strongly contested in the last 5 years; while studies of the motions of stars near the Sun find a bar that is both fast and small, direct observations of the Galactic central region agree on one that is significantly slower and larger.

The new study, by an international team of scientists suggests an insightful solution to this discrepancy. Analyzing state-of-the-art galaxy formation simulations of the Milky Way, they show that both the bar's size and its rotational speed fluctuate rapidly in time, causing the bar to appear up to twice as long and rotate 20 percent faster at certain times.

The bar pulsations result from its regular encounters with the Galactic spiral arms, in what can be described as a "cosmic dance." As the bar and spiral arm approach each other, their mutual attraction due to gravity makes the bar slow down and the spiral speed up. Once connected, the two structures move as one and the bar appears much longer and slower than it actually is. As the dancers split apart, the bar speeds up while the spiral slows back down.

T Hilmi et al. Fluctuations in galactic bar parameters due to bar–spiral interaction, Monthly Notices of the Royal Astronomical Society (2020). DOI: 10.1093/mnras/staa1934

https://phys.org/news/2020-08-galactic-bar-paradox-cosmic.html?utm_...

Comment by Dr. Krishna Kumari Challa on August 26, 2020 at 5:10am

New imaging technique helps resolve nanodomains, chemical composition in cell membranes

Jin Lu et al. Single‐Molecule 3D Orientation Imaging Reveals Nanoscale Compositional Heterogeneity in Lipid Membranes, Angewandte Chemie International Edition (2020). DOI: 10.1002/anie.202006207

https://phys.org/news/2020-08-imaging-technique-nanodomains-chemica...

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Nanoengineered biosensors for early disease detection

Researchers have developed a cheaper, faster and ultrasensitive biosensors that use nanoengineered porous gold which more effectively detect early signs of disease, improving patient outcomes. This new diagnostic technique allows for direct detection of disease-specific miRNA, which wasn't previously possible.

This is especially important for patients at an early stage of a disease such as cancer, who do not have detectable amounts of other biomarkers, but may have a detectable quantity of exosomal miRNA biomarker.

The platform was nanoengineered by the team to read samples of blood, urine, saliva or plasma through a surface covered in a gold film, which has millions of tiny pores.

Hyunsoo Lim et al. A universal approach for the synthesis of mesoporous gold, palladium and platinum films for applications in electrocatalysis, Nature Protocols (2020). DOI: 10.1038/s41596-020-0359-8

https://phys.org/news/2020-08-nanoengineered-biosensors-early-disea...

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Physicists discover new two-dimensional ferroelectric material just two atoms thick

Two-dimensional materials are ultrathin membranes that hold promise for novel optoelectronic, thermal, and mechanical applications, including ultra-thin data-storage devices that would be both foldable and information dense.

Ferroelectric materials are those with an intrinsic dipole moment—a measure of the separation of positive and negative charges—that can be switched by an electric field.

Salvador Barraza-Lopez et al. Water Splits To Degrade Two-Dimensional Group-IV Monochalcogenides in Nanoseconds, ACS Central Science (2018). DOI: 10.1021/acscentsci.8b00589

https://phys.org/news/2020-08-physicists-two-dimensional-material.h...

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 8:16am

The False Logic behind Science Denial

Those who argue that COVID-19 isn’t a real threat are mirroring bogus attacks on global warming and evolution

https://www.scientificamerican.com/article/the-false-logic-behind-s...  

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How Birds Evolved Their Incredible Diversity

An analysis of 391 skulls shows that birds evolved surprisingly slowly, compared with their dinosaur forerunners

https://www.scientificamerican.com/article/how-birds-evolved-their-...

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Origami-inspired miniature manipulator improves precision and control of teleoperated surgical procedures

https://techxplore.com/news/2020-08-origami-inspired-miniature-prec...

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** 'Earth breathing': mountain erosion a missing piece in the climate puzzle

https://phys.org/news/2020-08-earth-mountain-erosion-piece-climate....

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Digging your own digital grave: How should you manage the data you leave behind?

https://techxplore.com/news/2020-08-digital-grave.html?utm_source=n...

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 7:59am

Scientists Are Figuring Out What Happens in The Skin When You Have Eczema

Scientists have pinpointed a bunch of processes that go wrong in the skin for people who have eczema (also known as atopic dermatitis), and it could help us figure out how to combat this chronic condition.

Earlier, researchers found a strong link between people lacking in a certain skin protein, and the risk of developing eczema. And in 2017, scientists built on those results to show exactly what goes wrong, and their results could even take us closer to an eczema cure.

For the past decade, scientists have known that eczema is associated with a genetic lack of filaggrin (filament aggregating protein) in the skin. This protein helps shape individual skin cells, and plays an important role in our skin's barrier function.

If a person has a genetic mutation that prevents proper filaggrin supply, they can develop skin conditions such as eczema or ichthyosis vulgaris, where skin cells don't shed, and instead pile up in a pattern that looks like fish scales.

But until recently, researchers weren't sure how eczema actually develops when filaggrin is lacking.

The breakthrough came in 2016, when scientists from Newcastle University in the UK in collaboration with GSK Stiefel tracked down a series of proteins and molecular pathways that lead to this insufferable skin problem.

They found that this deficiency alone could trigger a host of molecular changes in important regulatory mechanisms in the skin. This affected things like cell structure, barrier function, and even how cells got inflamed and responded to stress

They found that several of the proteins they detected were similarly altered in only those with eczema - just like the lab-based model had demonstrated.

Once scientists know for sure what goes on in the skin if you have the faulty filaggrin gene, they can start looking for drugs that can stop that from happening.

The study was published in the Journal of Allergy and Clinical Immunology.

https://www.sciencealert.com/scientists-are-figuring-out-what-happe...

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 7:53am

Researchers find method to regrow cartilage in the joints

Researchers at the Stanford University School of Medicine have discovered a way to regenerate, in mice and human tissue, the cushion of cartilage found in joints. 

 Loss of this slippery and shock-absorbing tissue layer, called articular cartilage, is responsible for many cases of joint pain and arthritis, which afflicts millions around the world .

Researchers now figured out how to regrow articular cartilage by first causing slight injury to the joint tissue, then using chemical signals to steer the growth of skeletal stem cells as the injuries heal.  

Cartilage has practically zero regenerative potential in adulthood, so once it's injured or gone, what we can do for patients has been very limited. It's extremely gratifying to find a way to help the body regrow this important tissue.

Source: Matthew P. Murphy et al. Articular cartilage regeneration by activated skeletal stem cells, Nature Medicine (2020). DOI: 10.1038/s41591-020-1013-2

Deshka S. Foster et al. Elucidating the fundamental fibrotic processes driving abdominal adhesion formation, Nature Communications (2020). DOI: 10.1038/s41467-020-17883-1

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 7:41am

Covid-19 news: Researchers find first case of coronavirus reinfection

Researchers say they have detected the first case of coronavirus reinfection

A 33-year-old man from Hong Kong was infected again 4½ months after he first caught the coronavirus

Researchers at the University of Hong Kong say they have documented the first case of a person being reinfected with the coronavirus. The team analysed virus samples taken from a man when he first tested positive for the coronavirus in late March, and again when he tested positive for a second time in mid-August. They discovered several differences in the sequences of the virus from the first and second infections, suggesting the man had been infected with two separate strains of the virus, rather than one long-lasting infection. Their findings have been accepted for publication in the Clinical Infectious Diseases journal.

Source: https://www.newscientist.com/article/2237475-covid-19-news-research...

https://www.livescience.com/coronavirus-confirmed-case-reinfection....

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** Could COVID-19 in wastewater be infectious?

International Study Led by Researchers at Ben-Gurion University Indicates Wastewater Containing COVID-19 May Be A Serious Threat

https://www.eurekalert.org/pub_releases/2020-08/aabu-cci082320.php

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 7:26am

**Using a smartphone and audio software to pick a physical lock

A trio of researchers has found a way to pick an ordinary physical lock using a smartphone with special software

With traditional locks, such as those found on the front doors of most homes, a person inserts the proper (metal) key and then turns it. Doing so pushes up a series of pins in the lock by a certain amount based on the ridges on the key. When the pins are pushed in a way that matches a preset condition, the tumbler can turn, retracting the metal piece of the door assembly from its berth, allowing the door to open. In this new effort, the researchers have found that it is possible to record the sounds made as the key comes into contact with the pins and then as the pins move upward, and use software to recreate the conditions that produce the same noises. Those conditions can be used to fabricate a metal key to unlock the door. The result is a system the team calls SpiKey, which involves use of a smartphone to record lock clicks, decipher them and then create a key signature for use in creating a new metal key.

Soundarya Ramesh et al. Listen to Your Key, Proceedings of the 21st International Workshop on Mobile Computing Systems and Applications (2020). DOI: 10.1145/3376897.3377853 . PDF.

https://techxplore.com/news/2020-08-smartphone-audio-software-physi...

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 7:22am

Locust swarm could improve collision avoidance

Plagues of locusts, containing millions of insects, fly across the sky to attack crops, but the individual insects do not collide with each other within these massive swarms. Now a team of engineers is creating a low-power collision detector that mimics the locust avoidance response and could help robots, drones and even self-driving cars avoid collisions.

Mechanism of locusts: Locusts are unusual because they use a single, specialized neuron, called the Lobula Giant Movement Detector (LGMD), to avoid collisions.

The neuron receives two different signals. An image of an approaching locust falls on the avoiding locust's eye. The closer the invading locust gets, the larger the image and the stronger this excitation signal becomes. The other input is the change in angular velocity of the invading locust with respect to the avoiding locust.

Because the neuron has two branches, the locust computes the changes in these two inputs and realizes that something is going to collide.  So the avoiding locust changes direction.

The researchers developed a compact, nanoscale collision detector using monolayer molybdenum sulfide as a photodetector. They placed the photo detector on top of a programmable floating gate memory architecture that can mimic the locust's  neuron response using only a tiny amount of energy.

A low-power biomimetic collision detector based on an in-memory molybdenum disulfide photodetector, Nature Electronics (2020). DOI: 10.1038/s41928-020-00466-9 , www.nature.com/articles/s41928-020-00466-9

https://techxplore.com/news/2020-08-locust-swarm-collision.html?utm...

Comment by Dr. Krishna Kumari Challa on August 25, 2020 at 7:17am

**Study suggests hot nights pose greater threat to public health th...

Hong Kong has been experiencing hotter summers and more scorcher days in recent years due to climate change and heat island effect. Amid the increasing number of "hot nights," it is found that consecutive "hot nights" are more detrimental to human health than "very hot days," although the actual temperature does not reach the level of daytime, according to a collaborative research conducted by the Institute of Future Cities at The Chinese University of Hong Kong (CUHK), as well as researchers from the University of Hong Kong. The research also identified that lack of urban greenery and poor air ventilation in a high-density context are factors that lead to more "hot nights" than "hot days" in some areas. The team suggests that better urban planning and building design are long-term mitigation measures.

 Amid the increasing number of "hot nights," it is found that consecutive "hot nights" are more detrimental to human health than "very hot days," although the actual temperature does not reach the level of daytime, according to a collaborative research . The research also identified that lack of urban greenery and poor air ventilation in a high-density context are factors that lead to more "hot nights" than "hot days" in some areas. 

Apparently consecutive "hot nights" brought more health problems compared with "very hot days," especially for five or more consecutive "hot nights." It was also found that when consecutive "very hot days" were joined with consecutive "hot nights," such as two consecutive "very hot days" with three "hot nights," the health impact was significantly amplified, compared with only consecutive "very hot days." Moreover, females and older adults were determined to be relatively more vulnerable to extreme hot weather.

https://phys.org/news/2020-08-hot-nights-pose-greater-threat.html?u...

Restricting sleep may affect emotional reactions

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