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Comment by Dr. Krishna Kumari Challa on October 2, 2021 at 9:27am

'Fight or flight' – unless internal clocks are disrupted, study in mice shows

For humans and animals, many aspects of normal behavior and physiology rely on the proper functioning of the body's circadian clocks.

Here's how it's supposed to work: Your brain sends signals to your body to release different hormones at certain times of the day. For example, you get a boost of the hormone cortisol—nature's built-in alarm system—right before you usually wake up.

But hormone release actually relies on the interconnected activity of clocks in more than one part of the brain. New research from Washington University in St. Louis shows how daily release of glucocorticoids depends on coordinated clock-gene and neuronal activity rhythms in neurons found in two parts of the hypothalamus, the suprachiasmatic nucleus (SCN) and paraventricular nucleus (PVN).

The new study, conducted with freely behaving mice, is published Oct. 1 in Nature Communications.

Normal behavior and physiology depends on a near 24-hour circadian release of various hormones. When hormone release is disrupted, it can lead to numerous pathologies, including affective disorders like anxiety and depression and metabolic disorders like diabetes and obesity.

The daily timing of hormone release is controlled by the SCN. Located in the hypothalamus, just above where the optic nerves cross, neurons in the SCN send daily signals that are decoded in other parts of the brain that talk to the adrenal glands and the body's endocrine system.

"Cortisol in humans (corticosterone in mice) is more typically known as a stress hormone involved in the 'fight or flight' response. But the stress of waking up and preparing for the day is one of the biggest regular stressors to the body. Having a huge amount of this glucocorticoid released right as you wake up seems to help you gear up for the day.

Circadian neurons in the paraventricular nucleus entrain and sustain daily rhythms in glucocorticoids, Nature Communications (2021). DOI: 10.1038/s41467-021-25959-9

https://phys.org/news/2021-10-flight-internal-clocks-disrupted-mice...

Comment by Dr. Krishna Kumari Challa on October 1, 2021 at 9:45am

Two things affect the net sunlight reaching the Earth: the Sun's brightness and the planet's reflectivity. The changes in Earth's albedo observed by the researchers did not correlate with periodic changes in the Sun's brightness, so that means changes in Earth's reflectiveness are caused by something on the Earth.

Specifically, there has been a reduction of bright, reflective low-lying clouds over the eastern Pacific Ocean in the most recent years, according to satellite measurements made as part of NASA's Clouds and the Earth's Radiant Energy System (CERES) project.

That's the same area, off the west coasts of North and South America, where increases in sea surface temperatures have been recorded because of the reversal of a climatic condition called the Pacific Decadal Oscillation, with likely connections to global climate change.

The dimming of the Earth can also be seen in terms of how much more solar energy is being captured by Earth's climate system. Once this significant additional solar energy is in Earth's atmosphere and oceans, it may contribute to global warming , as the extra sunlight is of the same magnitude as the total anthropogenic climate forcing over the last two decades.

P. R. Goode et al, Earth's Albedo 1998–2017 as Measured From Earthshine, Geophysical Research Letters (2021). DOI: 10.1029/2021GL094888

https://phys.org/news/2021-09-earth-dimming-due-climate.html?utm_so...

Part 2

Comment by Dr. Krishna Kumari Challa on October 1, 2021 at 9:44am

Earth is dimming due to climate change

Warming ocean waters have caused a drop in the brightness of the Earth, according to a new study.

Researchers used decades of measurements of earthshine—the light reflected from Earth that illuminates the surface of the Moon—as well as satellite measurements to find that there has been a significant drop in Earth's reflectance, or albedo, over the past two decades.

The Earth is now reflecting about half a watt less light per square meter than it was 20 years ago, with most of the drop occurring in the last three years of earthshine data, according to the new study in the AGU journal Geophysical Research Letters, which publishes high-impact, short-format reports with immediate implications spanning all Earth and space sciences.

That's the equivalent of 0.5% decrease in the Earth's reflectance. Earth reflects about 30% of the sunlight that shines on it.

Part 1

Comment by Dr. Krishna Kumari Challa on October 1, 2021 at 8:38am

The more finely the story was shuffled, the more the fractal structures of the network patterns were disrupted.

Since the disruptions in those fractal patterns seemed directly linked with how well people could make sense of the story, this finding may provide clues about how our brain structures work together to understand what is happening in the narrative."

The fractal network patterns were surprisingly similar across people: patterns from one group could be used to accurately estimate what part of the story another group was listening to.

The team also studied which brain structures were interacting to produce these fractal patterns. The results show that the smallest scale (first-order) interactions occurred in brain regions that process raw sounds. Second-order interactions linked these raw sounds with speech processing regions, and third-order interactions linked sound and speech areas with a network of visual processing regions. The largest-scale (fourth-order) interactions linked these auditory and visual sensory networks with brain structures that support high-level thinking. According to the researchers, when these networks organize at multiple scales, this may show how the brain processes raw sensory information into complex thought—from raw sounds, to speech, to visualization, to full-on understanding.

The researchers' computational framework can also be applied to areas beyond neuroscience and the team has already begun using an analogous approach to explore interactions in stock prices and animal migration patterns.

High-level cognition during story listening is reflected in high-order dynamic correlations in neural activity patterns, Nature Communications (2021). DOI: 10.1038/s41467-021-25876-x

https://medicalxpress.com/news/2021-09-fractal-brain-networks-compl...

Comment by Dr. Krishna Kumari Challa on October 1, 2021 at 8:38am

How complex thoughts take place in the brain

Understanding how the human brain produces complex thought is daunting given its intricacy and scale. The brain contains approximately 100 billion neurons that coordinate activity through 100 trillion connections, and those connections are organized into networks that are often similar from one person to the next. A Dartmouth study has found a new way to look at brain networks using the mathematical notion of fractals, to convey communication patterns between different brain regions as people listened to a short story. The results are published in Nature Communications.

To generate our thoughts, our brains create  amazing lightning storm of connection patterns. The patterns look beautiful, but they are also incredibly complicated. Our mathematical framework lets us quantify how those patterns relate at different scales, and how they change over time.

In the field of geometry, fractals are shapes that appear similar at different scales. Within a fractal, shapes and patterns are repeated in an infinite cascade, such as spirals comprised of smaller spirals that are in turn comprised of still-smaller spirals, and so on. Dartmouth's study shows that brain networks organize in a similar way: patterns of brain interactions are mirrored simultaneously at different scales. When people engage in complex thoughts, their networks seem to spontaneously organize into fractal-like patterns. When those thoughts are disrupted, the fractal patterns become scrambled and lose their integrity.

The researchers developed a mathematical framework that identifies similarities in network interactions at different scales or "orders." When brain structures do not exhibit any consistent patterns of interaction, the team referred to this as a "zero-order" pattern. When individual pairs of brain structures interact, this is called a "first-order" pattern. "Second-order" patterns refer to similar patterns of interactions in different sets of brain structures, at different scales. When patterns of interaction become fractal— "first-order" or higher— the order denotes the number of times the patterns are repeated at different scales.

The study shows that when people listened to an audio recording of a 10-minute story, their brain networks spontaneously organized into fourth-order network patterns. However, this organization was disrupted when people listened to altered versions of the recording. For instance, when the story's paragraphs were randomly shuffled, preserving some but not all of the story's meaning, people's brain networks displayed only second-order patterns. When every word of the story was shuffled, this disrupted all but the lowest level (zero-order) patterns.

Part 1

Comment by Dr. Krishna Kumari Challa on October 1, 2021 at 8:27am

Study unveils the quantum nature of the interaction between photons and free electrons

For several decades, physicists have known that light can be described simultaneously as a wave and a particle. This fascinating 'duality' of light is due to the classical and quantum nature of electromagnetic excitations, the processes through which electromagnetic fields are produced.

So far, in all experiments in which light interacts with free electrons, it has been described as a wave. Researchers at Technion—Israel Institute of Technology, however, have recently gathered the first experimental evidence revealing the quantum nature of the interaction between photons and free electrons. Their findings, published in Science, could have important implications for future research investigating photons and their interaction with free electrons.

Raphael Dahan et al, Imprinting the quantum statistics of photons on free electrons, Science (2021). DOI: 10.1126/science.abj7128

Ofer Kfir, Entanglements of Electrons and Cavity Photons in the Strong-Coupling Regime, Physical Review Letters (2019). DOI: 10.1103/PhysRevLett.123.103602

Valerio Di Giulio et al, Probing quantum optical excitations with fast electrons, Optica (2019). DOI: 10.1364/OPTICA.6.001524

https://phys.org/news/2021-09-unveils-quantum-nature-interaction-ph...

Comment by Dr. Krishna Kumari Challa on October 1, 2021 at 8:04am

Toxic DNA buildup in eyes may drive blinding macular degeneration

Common HIV drugs could stop vision loss, research suggests

Damaging DNA builds up in the eyes of patients with geographic atrophy, an untreatable, poorly understood form of age-related macular degeneration that causes blindness, new research reveals. Based on the discovery, the researchers think it may be possible to treat the disease with common HIV drugs or an even safer alternative.

Geographic atrophy is an advanced form of age-related macular degeneration, a potentially blinding disease estimated to affect 200 million people around the world. The disease ultimately destroys vital cells in the retina, the light-sensing portion of the eye

A harmful DNA, known as Alu cDNA, was previously discovered to be manufactured in the cytoplasm. The new findings offer insights into how geographic atrophy progresses over time. This finding in human eyes that the levels of toxic Alu cDNA are highest at the leading edge of the geographic atrophy lesion provides strong evidence that it is responsible for this expansion over time that leads to vision loss.

As Alu DNA accumulates in the eye, it triggers harmful inflammation via a part of the immune system called the inflammasome. The researchers identified how this happens, discovering a previously unknown structural facet of Alu that triggers the immune mechanism that leads to the death of the vital retinal cells.

That's where HIV drugs called nucleoside reverse transcriptase inhibitors, or NRTIs, could come in. The researchers' new work in lab mice suggests these drugs, or safer derivatives known as Kamuvudines, could block the harmful inflammation and protect against retinal cell death.

Alu complementary DNA is enriched in atrophic macular degeneration and triggers retinal pigmented epithelium toxicity via cytosolic innate immunity. Science Advances, 2021; 7 (40) DOI: 10.1126/sciadv.abj3658

https://www.sciencedaily.com/releases/2021/09/210930101425.htm

Comment by Dr. Krishna Kumari Challa on September 30, 2021 at 9:57am

Breath tests could sniff out COVID-19

Since May 2021, drivers crossing into Singapore at the Tuas Checkpoint have been required to breathe into a cigar-sized mouthpiece connected to a mass spectrometer. In less than a minute, the device analyzes the breath samples for COVID-19. According to a new feature article in Chemical & Engineering News, such breath-based diagnostics might be a fast, cheap way to detect infection, although challenges exist.

More than a year into the pandemic, PCR-based assays—which require samples to be collected from patients' nasal passages with a long cotton swab—remain the gold standard for COVID-19 diagnosis. However, such tests are uncomfortable, slow and relatively expensive.

That's why several companies have launched breathalyzer-like tests to detect SARS-CoV-2 infection. These tests rely on altered ratios of volatile organic compounds (VOCs) in exhaled breath, which reflect metabolic changes triggered by the virus. But questions about whether the technology is sufficiently sensitive and reproducible are still unanswered. 

One challenge is that researchers haven't sufficiently defined the levels of VOCs in the breath of healthy people, which makes it difficult to accurately measure when someone's exhalation deviates from the norm. As a result, some breath-based tests have had disappointing results when used in real life. Also, some VOCs change similarly in response to different viruses or conditions, making it important to identify unique patterns or ratios of biomarkers that change only upon infection with SARS-CoV-2. Scientists in the field are hopeful that continued standardization and validation will eventually create a robust breath-based diagnostic that might even be able to detect infection earlier than PCR-based tests, before a person begins shedding the virus.

https://phys.org/news/2021-09-covid-.html?utm_source=nwletter&u...

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Comment by Dr. Krishna Kumari Challa on September 30, 2021 at 9:52am

How mercury gets into the sea

Mercury released into the atmosphere by industry enters the sea and from there makes its way into the food chain. Now, an analysis by researchers has revealed how the harmful substance enters seawater in the first place. This is not primarily via rainfall, as previously assumed, but rather also involves gas exchange. Measures to reduce mercury emissions could therefore take effect faster than previously thought.

Every year, 2,000 metric tons of gaseous mercury are released into the atmosphere by coal-fired power stations and mining activities. The harmful substance then adopts various chemical forms as it circulates between the air, soil and water in a complex cycle. Mercury is particularly dangerous in the sea, where it accumulates in fish in the form of highly toxic methylmercury. When this compound enters the human body due to the consumption of fish, it can have an adverse effect on brain development in children and cause cardiovascular diseases in adults.

It's estimated that human activities have tripled the amount of mercury in the surface ocean  since the onset of industrialization. Those are just assumptions, however, as there are no collector stations for precipitation over the sea.

The gap was closed by analyzing seawater samples using a new method that allows researchers to distinguish whether mercury originates from precipitation or entered the sea via gas exchange, . Known as "fingerprinting," this technique is based on the measurement of tiny weight differences between naturally occurring mercury atoms, known as isotopes.

The analyses revealed that—contrary to previous assumptions—only about half of the mercury in the sea originates from precipitation, while the other half enters the oceans due to the uptake of gaseous mercury.

Researchers suspect  that mercury uptake by plants drives more of the heavy metal to be deposited on land, where it is safely sequestered in soils and poses less of a risk to humans.

The new findings are also important for the implementation of the Minamata Convention of 2013, whereby 133 countries committed to reducing mercury emissions: "If less mercury enters the sea via rainfall, a reduction in emissions could cause mercury levels in seawater to drop faster than anticipated."

Mercury stable isotopes constrain atmospheric sources to the Ocean, Nature (2021). DOI: 10.1038/s41586-021-03859-8 , www.nature.com/articles/s41586-021-03859-8

https://phys.org/news/2021-09-mercury-sea.html?utm_source=nwletter&...

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Comment by Dr. Krishna Kumari Challa on September 30, 2021 at 9:43am

Making Music from Proteins

Researchers reporting in ACS Nano have found a way to represent a protein’s structure as music.

A Self-Consistent Sonification Method to Translate Amino Acid Sequences into Musical Compositions and Application in Protein Design using Artificial Intelligence.

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