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...

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

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

'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...

A breathing tube through the butt could be an alternative to mechanical ventilators

Inspired by animals that breathe through their butts, scientists show that mammals can also harness the incredible breathing ability of our butts.

To survive in extreme low-oxygen conditions deep in the ocean, fish and other creatures have developed remarkable adaptations. For example, sea spiders, loaches, and catfish evolved the ability to breathe through their butts. And they might not be the only butt breathers out there. 

A recent study in the journal Med now suggests that mammals, humans included, may be able to breathe through their rear ends as well. Mice, rats, and pigs could all stave off the devastating effects of oxygen deprivation if given an oxygen enema. But could this new method provide temporary oxygen while a patient awaits a ventilator?

Part1

While we often consider the butt as the exit for waste in our body, it is also an entryway with lifesaving potential. After all, humans and plenty of other mammals can absorb medications rectally. That’s because there’s a lot of blood vessels in the area, allowing medicine easy entry. 

But medicine is specially designed to maximize absorption in the body. Oxygen doesn’t have nearly as easy a path towards entry into the bloodstream through the rectum because of the mucus membrane mammals have on the intestines. There are also important anatomical differences between our intestines and those of fish that already harness this ability. Animals that can breathe through their butts, like loaches, had a much thinner epithelium in their guts and a lot less mucus. During the course of early development, a butt-breathing genetic pathway is turned on that helps dictate the structure of the intestine. When it’s all said and done, the posterior end of the intestine is equipped with all the structures necessary for respiration (and gas exchange).

Would this mucus prevent oxygenation in mice? In the first experiment, researchers used a model of oxygen deprivation in mice, preventing them from breathing through their lungs. The control group didn’t receive any intestinal ventilation, one group received oxygen through an anal catheter, and the final group had the mucus layer on their intestines “scrubbed” before receiving anal ventilation.

Remarkably, the mice supplied oxygen through their anus had elevated oxygen levels in their blood. The final group that also had their intestinal mucus scrubbed fared even better, surviving the longest in the low-oxygen conditions — five times as long as the control group. This experiment proved that there is potential for mammals to breathe through their butt, however, the mucus layer covering the intestinal epithelial cells makes it more difficult.

In a clinical setting, scrubbing the mucus off of a person’s intestines isn’t really feasible, and doesn’t sound like a pleasant experience. But using a method akin to an enema may work, by infusing safe, oxygenated liquid through the butt. This liquid, called perfluorodecalin, could safely store and deliver oxygen via an enema. Due to the properties of this liquid, it doesn’t need to scrub the mucus off of the intestines, meaning less discomfort and abrasion. Oxygen diffuses into the bloodstream while carbon dioxide diffuses out. Since it holds a lot of oxygen and carbon dioxide very easily, it is also delivered safely to the lungs, and is already in clinical use. 

Part2

During COVID-19, many hospitals find themselves short on ventilators. During the pandemic, many will require the use of a ventilator for an average of 15 days, while a few people will need significantly more time. Ventilators aren’t something that a person can use for one day and then get discharged. The first wave of people requiring ventilators will receive them immediately. However, someone whose lungs fail the next day may need to survive for two weeks without one.

https://next.massivesci.com/articles/rectal-breathing-oxygen-enema-...

Part 3

The Scientific Problem of Consciousness

Primordial 'hyper-eye' discovered

An international research team has found an eye system in trilobites of the suborder Phacopina from the Devonian (390 million years ago) that is unique in the animal kingdom: each of the about 200 lenses of a hyper-facet eye spans a group of six normal compound-eye-facets, forming a compound eye itself. In addition to the hyper-facetted eyes, the researchers identified a structure that they think to be a local neural network which directly processed the information from this special eye, and an optic nerve that carried information from the eye to the brain. The article, "A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites," has been published in Scientific Reports.

B. Schoenemann, E. N. K. Clarkson, C. Bartels, W. Südkamp, G. E. Rössner, U. Ryck. A 390 million-year-old hyper-compound eye in Devonian phacopid trilobites. Scientific Reports, 2021; 11 (1) DOI: 10.1038/s41598-021-98740-z

https://www.sciencedaily.com/releases/2021/09/210930101416.htm

Covid pill cuts hospitalizations by 50%

Oral drug molnupiravir for Covid-19 was shown to reduce the chance newly infected patients were hospitalized by 50 percent. A simple pill to treat the coronavirus has been sought since the start of the pandemic and Friday's announcement was hailed as a major step towards that goal.

In a late stage clinical trial, Merck and its partner Ridgeback Therapeutics evaluated data from 775 patients -- roughly half of whom received either a five-day course of the pill, while the other received a placebo.

All the patients had lab-confirmed Covid-19 with symptoms that developed within five days of them being assigned to their respective groups.

Of the patients who received molnupiravir, 7.3 percent were hospitalized by day 29, compared to 14.1 percent of those on a placebo -- a relative risk reduction of around 50 percent.

There were also eight deaths in the placebo group but, significantly, none in the drug group.

Efficacy was said to hold up against variants of concern, including Delta, and the drug had a good safety profile.

The results were compelling enough that an independent data monitoring committee in consultation with the FDA decided to halt the trial early, which could indicate they felt it would be unethical to continue with a placebo arm.

Molnupiravir belongs to a class of antiviral drugs called "polymerase inhibitors," which work by targeting an enzyme that viruses need to copy their genetic material, and introducing mutations that leave them unable to replicate.

Such drugs are expected to be more variant-proof than monoclonal antibody treatments, which target a surface protein of the virus that is continually evolving.

It was initially developed as an inhibitor of influenza and respiratory syncytial virus, two other important acute respiratory infections, by a team at Emory University.

"If it is proven to be very safe and proven to be effective, then it can be used broadly, irrespective of the diagnosis, to treat and prevent multiple respiratory infections.

But experts also cautioned they would like to see the complete underlying data. They also stress that this is no substitute for vaccination. It's not a miracle cure but a companion tool. And if the drug is used carelessly, the public may end up developing resistance to the drug.

Experts also said it would be crucial to administer the drug early. Since it isn't always clear who is at risk for developing severe disease, it would have the greatest impact if it is cheap enough to distribute widely.

https://researchnews.cc/news/9225/Merck-s-Covid-pill-hailed-after-c...

Mystery of the Pulsating Spider

The promise of medical science

Understanding and treating Necrotizing Enterocolitis in babies

2 win medicine Nobel for showing how we react to heat, touch

Two scientists won the Nobel Prize in medicine on Monday for their discoveries into how the human body perceives temperature and touch, revelations that could lead to new ways of treating pain or even heart disease.

 David Julius and Ardem Patapoutian separately identified receptors in the skin that respond to heat and pressure, and researchers are working on drugs to target them. Some hope the discoveries could eventually lead to pain treatments that reduce dependence on highly addictive opioids. 

Julius, of the University of California at San Francisco, used capsaicin, the active component in chili peppers, to help pinpoint the nerve sensors that respond to heat, the Nobel Committee said. Patapoutian, of Scripps Research Institute at La Jolla, California, found pressure-sensitive sensors in cells that respond to mechanical stimulation.

This really unlocks one of the secrets of nature. It's actually something that is crucial for our survival, so it's a very important and profound discovery.

Announcement of the 2021 Nobel Prize in Physiology or Medicine

https://medicalxpress.com/news/2021-10-nobel-prize-honors-discovery...

Exposure to deadly urban heat worldwide has tripled in recent decades, says study

A new study of more than 13,000 cities worldwide has found that the number of person-days in which inhabitants are exposed to extreme combinations of heat and humidity has tripled since the 1980s. The authors say the trend, which now affects nearly a quarter of the world's population, is the combined result of both rising temperatures and booming urban population growth. The study was published today in the Proceedings of the National Academy of Sciences.

Over recent decades, hundreds of millions have moved from rural areas to cities, which now hold more than half the world's population. There, temperatures are generally higher than in the countryside, because of sparse vegetation and abundant concrete, asphalt and other impermeable surfaces that tend to trap and concentrate heat —the so-called urban heat island effect.

 This has broad effects. It increases morbidity and mortality. It impacts people's ability to work, and results in lower economic output. It exacerbates pre-existing health conditions.

 Global urban population exposure to extreme heat, Proceedings of the National Academy of Sciences (2021). doi.org/10.1073/pnas.2024792118

Part1

The researchers combined infrared satellite imagery and readings from thousands of ground instruments to determine maximum daily heat and humidity readings in 13,115 cities, from 1983 to 2016. They defined extreme heat as 30 degrees Centigrade on the so-called "wet-bulb globe temperature" scale, a measurement that takes into account the multiplier effect of high humidity on human physiology. A wet-bulb reading of 30 is the rough equivalent of 106 degrees Fahrenheit on the so-called "real feel" heat index—the point at which even most healthy people find it hard to function outside for long, and the unhealthy might become very ill or even die.

To come up with a measure of person-days spent in such conditions, the researchers matched up the weather data with statistics on the cities' populations over the same time period.

The analysis revealed that the number of person-days in which city dwellers were exposed went from 40 billion per year in 1983 to 119 billion in 2016—a threefold increase. By 2016, 1.7 billion people were being subjected to such conditions on multiple days.

The most-affected cities tend to cluster in the low latitudes, but other areas are being affected, too. The worst-hit city in terms of person-days was Dhaka, the fast-growing capital of Bangladesh; it saw an increase of 575 million person-days of extreme heat over the study period. Its ballooning population alone—4 million in 1983, to 22 million today—caused 80 percent of the increased exposure. This does not mean that Dhaka did not see substantial warming—only that population growth was even more rapid. Other big cities showing similar population-heavy trends include Shanghai and Guangzhou, China; Yangon, Myanmar; Bangkok; Dubai; Hanoi; Khartoum; and various cities in Pakistan, India and the Arabian Peninsula.

https://phys.org/news/2021-10-exposure-deadly-urban-worldwide-tripl...

Part 2

Our DNA is becoming the world's tiniest hard drive

Our genetic code is millions of times more efficient at storing data than existing solutions, which are costly and use immense amounts of energy and space. In fact, we could get rid of hard drives and store all the digital data on the planet within a couple hundred pounds of DNA.

Using DNA as a high-density data storage medium holds the potential to forge breakthroughs in biosensing and biorecording technology and next-generation digital storage, but researchers haven't been able to overcome inefficiencies that would allow the technology to scale.

Now, researchers at Northwestern University propose a new method for recording information to DNA that takes minutes, rather than hours or days, to complete. The team used a novel enzymatic system to synthesize DNA that records rapidly changing environmental signals directly into DNA sequences, a method the paper's senior author said could change the way scientists study and record neurons inside the brain.

The research, "Recording Temporal Signals with Minutes Resolution Using Enzymatic DNA Synthesis," was published Thursday (Sept. 30) in the Journal of the American Chemical Society.

Namita Bhan et al, Recording Temporal Signals with Minutes Resolution Using Enzymatic DNA Synthesis, Journal of the American Chemical Society (2021). DOI: 10.1021/jacs.1c07331

https://phys.org/news/2021-10-dna-world-tiniest-hard.html?utm_sourc...

Announcement of the 2021 Nobel Prize in Physics

Three scientists won the Nobel Prize in physics Tuesday for work that found order in seeming disorder, helping to explain and predict complex forces of nature, including expanding our understanding of climate change.

Genes are individualists, not collectivists, during early fruit fly development

Active genes do not form clusters and share resources during early development in the fruit fly, according to a new study by researchers published in the journal Current Biology.

The study changes the way we think about how the molecular machinery functions in basic cellular mechanisms during the development of organisms.

The nucleus is the portion of the cell containing the vast majority of genetic information—including the complex jumble of long cables of DNA that make up the genome—in order to determine the behavior of that organism. Genes stored in the sequence of DNA encode not just the protein sequence required to express the trait associated with that gene, but also the information for when that protein sequence should be manufactured.

"The nucleus is an elaborate switchboard—the connection point for the vast array of information about the state of the cell's environment, which will be processed and responded to by a defined set of expressed protein products. Within this framework, this study asked if there exists cooperation between these hundreds of logic gates making individual decisions about when to manufacture their respective proteins.

part1

Within the environment of the nucleus, it would make sense that genes regulated by the same type of information would be concentrated in close proximity so that they might share resources, potentially lowering the energetic cost of regulation. Several previous experiments have shown a level of organization in the nucleus where genes occupy discrete domains. However, many of these studies use biochemical methods to define domains, rather than actually observing the physical position of the active genes within the nucleus.

In the Current Biology study, the researchers demonstrated that they could accurately identify the physical position of the active genes using a microscopy imaging procedure and fruit flies, a model organism commonly used in genetic and molecular research. The researchers examined how a fertilized fruit fly egg develops into a fully formed organism, a process that requires the activity of sets of genes, which become progressively activated during embryonic development.

Focusing on the earliest set of genes appearing in 90-minute-old fruit fly embryos, the researchers observed how a protein called Zelda regulates the genes' transcription by recruiting the enzyme RNA Polymerase II (Pol-II). Using high resolution microscopy and antibody staining, they visualized Pol-II at sites of nascent transcription on chromosomes.

By observing the positions of many genes using this method, they asked the question: Are genes found in clusters? The answer was no.

The researchers performed a series of follow-up experiments to test the notion of functional clustering, such as looking for gene expression changes when genes were found in close proximity, or signs of resources being shared among the genes visualized. Once again, they did not find evidence of clustering.

In contrast to the idea that genes are spatially clustered and share transcriptional resources—what one might call a "collectivist" model—the authors conclude that the data support an "individualist" model of gene control at early genome activation in fruit flies.

Spatial organization of transcribing loci during early genome activation in Drosophila, Current Biology (2021). DOI: 10.1016/j.cub.2021.09.027

https://phys.org/news/2021-10-genes-individualists-collectivists-ea...

New study uncovers brain circuits that control fear responses

Researchers  have discovered a brain mechanism that enables mice to override their instincts based on previous experience.

The study, published today in Neuron, identifies a new brain circuit in the ventral lateral geniculate nucleus (vLGN), an inhibitory structure in the brain. The neuroscientists found that when activity in this brain region was suppressed, animals were more likely to seek safety and escape from perceived danger, whereas activation of vLGN neurons completely abolished escape responses to imminent threats.

While it is normal to experience fear or anxiety in certain situations, we can adjust our fear responses depending on our knowledge or circumstances. For example, being woken up by loud blasts and bright lights nearby might evoke a fear reaction. But if you have experienced fireworks before, your knowledge will likely prevent such reactions and allow you to watch without fear. On the other hand, if you happen to be in a war zone, your fear reaction might be strongly increased.

While many brain regions have previously been shown to be involved in processing perceived danger and mediating fear reactions, the mechanisms of how these reactions are controlled are still unclear. Such control is crucial since its impairment can lead to anxiety disorders such as phobias or post-traumatic stress disorders (PTSD), in which the circuits in the brain associated with fear and anxiety are thought to become overactive, leading to pathologically increased fear responses.

The new study took advantage of an established experimental paradigm in which mice escape to a shelter in response to an overhead expanding dark shadow. This looming stimulus simulates a predator moving towards the animal from above.

The researchers found that the vLGN could control escape behavior depending on the animal's knowledge gained through previous experience, and on its assessment of risk in its current environment. When mice were not expecting a threat and felt safe, the activity of a subset of inhibitory neurons in the vLGN was high, which in turn could inhibit threat reactions. In contrast, when mice expected danger, activity in these neurons was low, which made the animals more likely to escape and seek safety.

vLGN specifically inhibits neurons in the superior colliculus that respond to visual threats and thereby specifically blocks the pathway in the brain that mediates reactions to such threats—something the animal sees that could pose a danger like an approaching predator.

Flexible inhibitory control of visually-evoked defensive behaviour by the ventral lateral geniculate nucleus, Neuron (2021). DOI: 10.1016/j.neuron.2021.09.003

https://medicalxpress.com/news/2021-10-uncovers-brain-circuits-resp...

Age and aging have critical effects on the gut microbiome

Researchers have found that aging produces significant changes in the microbiome of the human small intestine distinct from those caused by medications or illness burden. The findings were published in the journal Cell Reports.

By teasing out the microbial changes that occur in the small bowel with age, medication use and diseases, researchers hope to identify unique components of the microbial community to target for therapeutics and interventions that could promote healthy aging.

Research exploring the gut microbiome, and its impact on health, has relied predominantly on fecal samples, which do not represent the entire gut. So  in their present study, investigators analyzed samples from the small intestine for examination of the microbiome and its relationship with aging.

This study is the first of its kind to examine the microbial composition of the small intestine of subjects 18 years of age to 80. Scientists now know that certain microbial populations are influenced more by medications, while others are more affected by certain diseases. Now researchers have identified specific microbes that appear to be only influenced by the chronological age of the person.

The 21st century has been referred to as the "era of the gut microbiome" as scientists turn considerable attention to the role trillions of gut bacteria, fungi and viruses may play in human health and disease. The microbiome is the name given to the genes that live in these cells. Studies have suggested that disturbances in the constellations of the microbial universe may lead to critical illnesses, including gastroenterological diseases, diabetes, obesity, and some neurological disorders.

While researchers know that microbial diversity in stool decreases with age, investigators now identified bacteria in the small bowel they refer to as "disruptors" that increase and could be troublesome.
Coliforms are normal residents of the intestine. They found that when these rod-shaped microbes become too abundant in the small bowel–as they do as we get older–they exert a negative influence on the rest of the microbial population. They are like weeds in a garden.

Investigators also found that as people age, the bacteria in the small intestine change from microbes that prefer oxygen to those that can survive with less oxygen, something they hope to understand as the research continues.

Gabriela Leite, Mark Pimentel, Gillian M. Barlow, Christine Chang, Ava Hosseini, Jiajing Wang, Gonzalo Parodi, Rashin Sedighi, Ali Rezaie, Ruchi Mathur. Age and the aging process significantly alter the small bowel microbiome. Cell Reports, 2021; 36 (13): 109765 DOI: 10.1016/j.celrep.2021.109765

https://researchnews.cc/news/9274/Age-and-aging-have-critical-effec...

PLOS Pathogens to offer authors seamless data deposition to Dryad

The Public Library of Science (PLOS) today announced that PLOS Pathogens is introducing a new technology solution that makes depositing data simpler and more accessible for our authors. As part of a one-year trial beginning October 5, 2021, PLOS Pathogens authors now have the option to upload their data files directly to Dryad Digital Repository (https://datadryad.org/stash/) during manuscript submission or revision—without even leaving our submission system. PLOS Pathogens is among the first journals in our field to offer this new service. Thanks to a grant from the Wellcome Trust (https://plos.io/3oAOeiu), datasets that are part of the trial will be hosted in perpetuity at no cost to authors.

Researchers rely on access to scientific data to enhance their understanding of published research, for purposes of verification, replication and reanalysis, to guide future investigations, and to inform systematic reviews or meta-analyses. Depositing data in a repository (as opposed to offering it upon request or publishing as Supporting Information) further prevents data loss, improves discoverability, and removes barriers to replication and reuse. This new integrated solution means that it takes just minutes to upload a dataset and receive a unique, citable Dryad DOI. If a manuscript is accepted for publication, the associated dataset will undergo Dryad’s screening and curatorial process and become public on the site, with links to and from the published research article.

Data repositories like Dryad offer important advantages, including data preservation and tracking, facilitating reproducibility, demonstrating rigor, and attracting citations. This integration offers a simple, intuitive interface that makes depositing data with Dryad a part of our authors' normal submission workflow. The process is no more challenging than uploading data as Supporting Information, but much more effective as a vehicle for sharing. The year-long trial will show whether a more streamlined process inspires authors to take advantage of the benefits of a data repository.

https://datadryad.org/stash/

https://www.eurekalert.org/news-releases/930457

Personalized Deep Brain Stimulation Therapy (DBS)

Health physicians have successfully treated a patient with severe depression by tapping into the specific brain circuit involved in depressive brain patterns and resetting them using the equivalent of a pacemaker for the brain.

Nobel in chemistry honors 'greener' way to build molecules

Two scientists won the Nobel Prize in chemistry Wednesday for finding an ingenious and environmentally cleaner way to build molecules—an approach now used to make a variety of compounds, including medicines and pesticides.

The work of Benjamin List and David W.C. MacMillan has allowed scientists to produce those molecules more cheaply, efficiently, safely and with significantly less hazardous waste.

It's already benefiting humankind greatly. It was the second day in a row that a Nobel rewarded work that had environmental implications.

Announcement of the 2021 Nobel Prize in Chemistry

Early human activities impacted Earth's atmosphere more than previously known

Did you think only industrial era impacted Earth's atmosphere? Then think again. Because ....

Several years ago, while analyzing ice core samples from Antarctica's James Ross Island, scientists noticed something unusual: a substantial increase in levels of black carbon that began around the year 1300 and continued to the modern day.

Black carbon, commonly referred to as soot, is a light-absorbing particle that comes from combustion sources such as biomass burning (e.g. forest fires) and, more recently, fossil fuel combustion. Working in collaboration with an international team of scientists from the United Kingdom, Austria, Norway, Germany, Australia, Argentina, and the U.S., McConnell, Chellman, and Mulvaney set out to uncover the origins of the unexpected increase in black carbon captured in the Antarctic ice.

The team's findings, which published this week in Nature, point to an unlikely source: ancient Māori land-burning practices in New Zealand, conducted at a scale that impacted the atmosphere across much of the Southern Hemisphere and dwarfed other preindustrial emissions in the region during the past 2,000 years.

The idea that humans at this time in history caused such a significant change in atmospheric black carbon through their land clearing activities is quite surprising.

We used to think that if you went back a few hundred years you'd be looking at a pristine, pre-industrial world, but it's clear from this study that humans have been impacting the environment over the Southern Ocean and the Antarctica Peninsula for at least the last 700 years.

To identify the source of the black carbon, the study team analyzed an array of six ice cores collected from James Ross Island and continental Antarctica using DRI's unique continuous ice-core analytical system. The method used to analyze black carbon in ice was first developed in McConnell's lab in 2007.

While the ice core from James Ross Island showed a notable increase in black carbon beginning around the year 1300, with levels tripling over the 700 years that followed and peaking during the 16^th and 17^th centuries, black carbon levels at sites in continental Antarctica during the same period of time stayed relatively stable.

Part 1

After consulting paleofire records from each of the three regions, only one viable possibility remained: New Zealand, where charcoal records showed a major increase in fire activity beginning about the year 1300. This date also coincided with the estimated arrival, colonization, and subsequent burning of much of New Zealand's forested areas by the Māori people.

This was a surprising conclusion, given New Zealand's relatively small land area and the distance (nearly 4,500 miles), that smoke would have travelled to reach the ice core site on James Ross Island.

"Compared to natural burning in places like the Amazon, or Southern Africa, or Australia, you wouldn't expect Māori burning in New Zealand to have a big impact, but it does over the Southern Ocean and the Antarctic Peninsula

--

The study findings are important for a number of reasons. First, the results have important implications for our understanding of Earth's atmosphere and climate. Modern climate models rely on accurate information about past climate to make projections for the future, especially on emissions and concentrations of light-absorbing black carbon linked to Earth's radiative balance. Although it is often assumed that human impacts during preindustrial times were negligible compared to background or natural burning, this study provides new evidence that emissions from human-related burning have impacted Earth's atmosphere and possibly its climate far earlier, and at scales far larger, than previously imagined.

part2

Second, fallout from biomass burning is rich in micronutrients such as iron. Phytoplankton growth in much of the Southern Ocean is nutrient-limited so the increased fallout from Māori burning probably resulted in centuries of enhanced phytoplankton growth in large areas of the Southern Hemisphere.

Third, the results refine what is known about the timing of the arrival of the Māori in New Zealand, one of the last habitable places on earth to be colonized by humans. Māori arrival dates based on radiocarbon dates vary from the 13^th to 14^th century, but the more precise dating made possible by the ice core records pinpoints the start of large scale burning by early Māori in New Zealand to 1297, with an uncertainty of 30 years.

"From this study and other previous work this team has done such as on 2,000-year old lead pollution in the Arctic from ancient Rome, it is clear that ice core records are very valuable for learning about past human impacts on the environment. "Even the most remote parts of Earth were not necessarily pristine in preindustrial times."

Hemispheric black carbon increase after the 13th-century Māori arrival in New Zealand, Nature (2021). DOI: 10.1038/s41586-021-03858-9

https://phys.org/news/2021-10-early-human-impacted-earth-atmosphere...

Part 3

How 'ice needles' weave patterns of stones in frozen landscapes

Nature is full of repeating patterns that are part of the beauty of our world. An international team, including a researcher from the University of Washington, used modern tools to explain repeating patterns of stones that form in cold landscapes.

The new study, published Oct. 5 in the Proceedings of the National Academy of Sciences, uses experimental tools to show how needles of ice growing randomly on frozen ground can gradually move rocks into regular, repeating patterns. The team, based mainly in China and Japan, uses a combination of novel experiments and computer modeling to describe these striking features with new theoretical insights.

"The presence of these amazing patterns that develop without any intervention from humans is pretty striking in nature.

One of the reasons for the patterns is needle ice. As the temperature drops, the moisture contained in the soil grows into spikes of ice crystals that protrude from the ground.

"When you go out in the backyard after a freezing night and you feel a little crunch under the foot, you're probably walking on needle ice.

As needle ice forms it tends to push up soil particles, and if there are any, small stones. More needle ice can form on patches of bare soil compared to rock-covered areas. The ice needles will slightly displace any remaining stones in the barer region. Over years, the stones begin to cluster in groups, leaving the bare patches essentially stone-free.

That kind of selective growth involves interesting feedbacks between the size of the stones, the moisture in the soil and the growth of the ice needles.

Watch a video that shows how this happens here:

https://movie-usa.glencoesoftware.com/video/10.1073/pnas.2110670118...

Anyuan Li et al, Ice needles weave patterns of stones in freezing landscapes, Proceedings of the National Academy of Sciences (2021). DOI: 10.1073/pnas.2110670118

https://www.washington.edu/news/2021/10/06/how-ice-needles-weave-pa...

Clinical Trial Testing Automatic Oxygen Control Device for Premature Infants

The consequences are dire for the health of a premature baby — too much oxygen can cause blindness, and too little oxygen can cause brain damage and other negative health effects. Some premature babies need the help of life-saving machines in a neonatal intensive care unit, or NICU, to provide oxygen that eases the struggle to take their first breaths. However, small, personalized adjustments — to either raise or lower the level of oxygen provided — must be made by hand under the careful attention of nurses and respiratory therapists. Now, a clinical trial will test a new device that could make those needed adjustments for premature babies in a NICU — automatically.

Emerging infectious disease caused by a tick-borne nairovirus identified in Japan

A previously unknown virus that can infect humans and cause disease has been identified by scientists in Japan. The novel infectious virus, named Yezo virus, is transmitted by tick bites and causes a disease characterized by fever and a reduction in blood platelets and leucocytes. The discovery was made by researchers at Hokkaido University  and the results have been published in the journal Nature Communications.

At least seven people have been infected with this new virus in Japan since 2014, but, so far, no deaths have been confirmed. The Yezo virus was discovered after a 41-year-old man was admitted to the hospital in 2019 with fever and leg pain after being bitten by an arthropod believed to be a tick while he was walking in a local forest in Hokkaido. He was treated and discharged after two weeks, but tests showed he had not been infected with any known viruses carried by ticks in the region. A second patient showed up with similar symptoms after a tick bite the following year.

Genetic analysis of viruses isolated from blood samples of the two patients found a new type of orthonairovirus, a class of nairovirus, that includes pathogens such as the Crimean-Congo haemorrhagic fever virus. The scientists named it Yezo virus, after a historical Japanese name for Hokkaido, a large island in the north of the country where the virus was discovered. The novel virus was found most closely related to Sulina virus and Tamdy virus, detected in Romania and Uzbekistan, respectively, the latter of which reportedly caused acute fever in humans recently in China.

The scientists then checked blood samples collected from hospital patients who showed similar symptoms after tick bites since 2014. They found additional positive samples from five patients. These patients, including the first two, had a fever and reduced blood platelets and leucocytes, and showed indicators of abnormal liver function.

To determine the likely source of the virus, the research team screened samples collected from wild animals in the area between 2010 and 2020. They found antibodies for the virus in Hokkaido shika deer and raccoons. They also found the virus RNA in three major species of ticks in Hokkaido. The Yezo virus seems to have established its distribution in Hokkaido, and it is highly likely that the virus causes the illness when it is transmitted to humans from animals via ticks.

1. Fumihiro Kodama, Hiroki Yamaguchi, Eunsil Park, Kango Tatemoto, Mariko Sashika, Ryo Nakao, Yurino Terauchi, Keita Mizuma, Yasuko Orba, Hiroaki Kariwa, Katsuro Hagiwara, Katsunori Okazaki, Akiko Goto, Rika Komagome, Masahiro Miyoshi, Takuya Ito, Kimiaki Yamano, Kentaro Yoshii, Chiaki Funaki, Mariko Ishizuka, Asako Shigeno, Yukari Itakura, Lesley Bell-Sakyi, Shunji Edagawa, Atsushi Nagasaka, Yoshihiro Sakoda, Hirofumi Sawa, Ken Maeda, Masayuki Saijo, Keita Matsuno. A novel nairovirus associated with acute febrile illness in Hokkaido, Japan. Nature Communications, 2021; 12 (1) DOI: 10.1038/s41467-021-25857-0

https://www.sciencedaily.com/releases/2021/10/211004104237.htm

Why do ducks move in a row in water?

Riding the waves keeps ducks in a row

The sight of ducklings paddling in a line behind their mother is a common sight in rivers and ponds.

But just why do they swim in that formation? Scientists think they have discovered the reason—which could have applications in maritime shipping too.

In a research paper published in the Journal of Fluid Mechanics, naval architecture experts conclude that ducklings benefit from 'wave riding' and 'wave passing."

Using a mathematical and numerical model, the researchers found that when a duckling swims at a 'sweet point' behind its mother a 'destructive wave interference phenomenon' occurs. This causes the wave drag of the duckling to turn positive meaning the baby bird is actually pushed forward by the wave.

Interestingly this wave-riding benefit appears to be passed down to the rest of the ducklings in the line formation. Starting from the third duckling the wave drag of individuals gradually tends towards zero, and a delicate dynamic equilibrium is achieved. Each individual under that equilibrium acts as a wave passer, passing the waves' energy to its trailing companion without any energy losses.

Wave riding and wave passing are probably the principal reasons for the evolution of swimming formation by waterfowl.

This study is the first to reveal the reasons why the formation movement of waterfowl can preserve individuals' energy expenditure.

These principles could be potentially applied to design modern freight carrying vessels, e.g. a water-train, to transport more cargoes without extra fuel cost.

Zhi-Ming Yuan et al, Wave-riding and wave-passing by ducklings in formation swimming, Journal of Fluid Mechanics (2021). DOI: 10.1017/jfm.2021.820

https://phys.org/news/2021-10-ducks-row.html?utm_source=nwletter&am...

Why fast charging reduces the capacity of a car battery

When lithium ions are forced rapidly through a battery, they might get stuck and turn into lithium metal, no longer able to move through the battery.

Fast charging is kind of the Holy Grail. It is what everyone who owns a lithium ion battery based device wants to be able to do.

Inside the battery, however, there is a lot of complicated chemistry that can be sensitive to how fast it is charged. Things can go wrong. Capacity loss is the most critical one.

It is possible to make batteries with very high capacity that might allow you to drive your electric car 1000 km, but after you've charged and discharged it a few times, you would lose about half of that capacity and range.

All rechargeable batteries deteriorate over time, but this negative effect is extra strong when the battery is subjected to fast charging. They have been able to see that the lithium ions, which are so important for the capacity of a battery, are converted into pure lithium metal and are no longer useful. And most importantly: this effect is greatly enhanced by fast charging.

During fast charging, the same number of ions move through the system, but much faster. All ions must find their place in the anode in a much shorter time.

When you charge at double speed, you have to move the same amount of ions and electrons in half the time. The most likely thing is you get these lithium ions building up and they just can't get to the graphite anymore. They get stuck there and there's a lot of heat, a lot of energy being put into them, and so they get reduced to lithium metal.

 Donal P. Finegan et al, Spatial dynamics of lithiation and lithium plating during high-rate operation of graphite electrodes, Energy & Environmental Science (2020). DOI: 10.1039/d0ee01191f

https://techxplore.com/news/2021-10-fast-capacity-car-battery.html?...

The thin line between science and pseudo-science

Scientists Finally Know Why Wisdom Teeth Only Emerge When We're Basically Adults

Homo sapiens don't grow their last few teeth until they're nearly out of the teenage years.

This mystery of the molars is a tricky one to solve, in spite of their emergence playing such a critical role in tracking shifts in our evolution. But researchers  now think they might have cracked it.

One of the mysteries of human biological development is how the precise synchrony between molar emergence and life history came about and how it is regulated. Turning the bones and teeth of 21 species of primate into 3D models, the researchers were able to work out that the timing of our adult molars has a lot to do with the delicate balance of biomechanics in our growing skulls.  

And it's 'safety' that seems to be behind our tardy tooth growth.

"It turns out that our jaws grow very slowly, likely due to our overall slow life histories and, in combination with our short faces, delays when a mechanically safe space – or a 'sweet spot,' if you will – is available, resulting in our very late ages at molar emergence.

The back molars in primates sit just in front of two temporomandibular joints, which together form a hinge between your jaw and the skull. Unlike other joints in our body, the two pivots have to operate in perfect sync with one another. They also need to transfer a fair degree of force onto one or more points to get you biting and chewing.

In biomechanics, this three-point-process is governed by principles within something called the constrained level model. Put a tooth in the wrong spot, and the forces produced under this model could be bad news for a jaw that simply isn't big enough to cope.

For species with longer jaws, the time it takes for the skull to develop a suitable structure for teeth closest to the muscles near the hinge is relatively brief.

Humans, with our significantly flatter faces, have no such luck, needing to wait until our skulls have developed to a point that the forces put on each set of adult molars won't damage our growing jaw.

Not only does this give us a new way to evaluate dental conditions, such as impacted molars, but it could help paleontologists to better understand the evolution of our unique jaws among our hominid ancestors.

https://www.science.org/doi/10.1126/sciadv.abj0335

Part 1

The adult forms of the teeth we use to grind our food into a paste typically emerge from our gums in three stages – at around 6, 12, and 18 years of age (give or take).

Other primates get their adult molars earlier. For all our similarities in growth stages, the chimpanzee (Pan troglodytes) gets their molars at 3, 6, and 12. The yellow baboon (Papio cynocephalus) has its last adult molars out by age seven, and the rhesus macaque (Macaca mulatta) is all done by the time they're six.

One important factor constraining the timing of when teeth can appear is space. If the jaw isn't big enough for an adult-sized dental set, there's no point in squeezing them in.

Humans don't exactly have a lot of mouth space as it is, with impacted wisdom teeth a major problem for our species. But this doesn't explain why they pop up so late in our lives, or why the very back ones seem to be increasingly causing trouble.

Having an empty space for a tooth to grow doesn't make it a good idea to put one there, though. Teeth don't crunch all on their own – there's a whole lot of muscles and bone supporting them, ensuring sufficient pressure can safely tear and grind up our food.

"This study provides a powerful new lens through which the long-known linkages among dental development, skull growth and maturational profiles.

https://www.sciencealert.com/we-now-know-why-we-don-t-get-our-wisdo...

part2

Chilean scientist plans to clean up mining with 'metal eating' bacteria

Starving microorganisms capable of surviving in extreme conditions have already managed to "eat" a nail in just three days.

In Chile, a scientist is testing "metal-eating" bacteria she hopes could help clean up the country's highly-polluting mining industry.

In her laboratory in Antofagasta, an industrial town 1,100-kilometers north of Santiago, 33-year-old biotechnologist Nadac Reales has been carrying out tests with extremophiles—organisms that live in extreme environments.

Reales came up with her idea while still at university as she was conducting tests at a mining plant using microorganisms to improve the extraction of copper.

The bacteria "live in an acidic environment that is practically unaffected by relatively high concentrations of most metals.

At first the bacteria took two months to disintegrate a nail."

But when starved, they had to adapt and find a way of feeding themselves.

After two years of trials, the result was a marked increase in the speed at which the bacteria "ate," devouring a nail in just three days. s "chemical and microbiological tests" have proved the bacteria are not harmful to humans or the environment.

https://phys.org/news/2021-10-chilean-scientist-metal-bacteria.html...

**

How modern physicists think

The science of physics has strived to find the best possible explanations for understanding matter and energy in the physical world across all scales of space and time. Modern physics is filled with complex concepts and ideas that have revolutionized the way we see (and don't see) the universe. The mysteries of the physical world are increasingly being revealed by physicists who delve into non-intuitive, unseen worlds, involving the subatomic, quantum and cosmological realms. But how do the brains of advanced physicists manage this feat, of thinking about worlds that can't be experienced?

In a recently published paper in npj Science of Learning, researchers at Carnegie Mellon University have found a way to decode the brain activity associated with individual abstract scientific concepts pertaining to matter and energy, such as fermion or dark matter. They investigated the thought processes of their fellow CMU physics faculty concerning advanced physics concepts by recording their brain activity using functional Magnetic Resonance Imaging (fMRI).

This study's goal was to discover how the brain organizes highly abstract scientific concepts. An encyclopedia organizes knowledge alphabetically, a library organizes it according to something like the Dewey Decimal System, but how does the brain of a physicist do it?

The study examined whether the activation patterns evoked by the different physics concepts could be grouped in terms of concept properties. One of the most novel findings was that the physicists' brains organized the concepts into those with measureable versus immeasurable size.

Part1

For a physicist, some concepts like dark matter, neutrinos or the multiverse, their magnitude is not measureable. And in the physicists' brains, the measureable versus immeasurable concepts are organized separately.

Of course, some parts of the brain organization of the physics professors resembled the organization in physics students' brains such as concepts that had a periodic nature. Light, radio waves and gamma rays have a periodic nature but concepts like buoyancy and the multiverse do not.

part2

The neurons in the human brain have a large number of computational capabilities with various characteristics, and experience determines which of those capabilities are put to use in various possible ways in combination with other brain regions to perform particular thinking tasks. For example, every healthy brain is prepared to learn the sounds of spoken language, but an infant's experience in a particular language environment shapes which phonemes of which language are learned.

The genius of civilization has been to use these brain capabilities to develop new skills and knowledge. What makes all of this possible is the adaptability of the human brain. We can use our ancient brains to think of new concepts, which are organized along new, underlying dimensions. An example of a "new" physics dimension significant in 20^th century, post-Newtonian physics is "immeasurability" (a property of dark matter, for example) that stands in contrast to the "measurability" of classical physics concepts, (such as torque or velocity). This new dimension is present in the brains of all university physics faculty tested. The scientific advances in physics were built with the new capabilities of human brains.

Another striking finding was the large degree of commonality across physicists in how their brains represented the concepts. Even though the physicists were trained in different universities, languages and cultures, there was a similarity in brain representations. This commonality in conceptual representations arises because the brain system that automatically comes into play for processing a given type of information is the one that is inherently best suited to that processing. As an analogy, consider that the parts of one's body that come into play to perform a given task are the best suited ones: to catch a tennis ball, a closing hand automatically comes into play, rather than a pair or knees or a mouth or an armpit. Similarly, when physicists are processing information about oscillation, the brain system that comes into play is the one that would normally process rhythmic events, such as dance movements or ripples in a pond. And that is the source of the commonality across people. It is the same brain regions in everyone that are recruited to process a given concept.

So the secret of teaching ancient brains new tricks, as the advance of civilization has repeatedly done, is to empower creative thinkers to develop new understandings and inventions, by building on or repurposing the inherent information processing capabilities of the human brain. By communicating these newly developed concepts to others, they will root themselves in the same information processing capabilities of the recipients' brains as the original developers used. Mass communication and education can propogate the advances to entire populations. Thus the march of science, technology and civilization continue to be driven by the most powerful entity on Earth, the human brain.

Robert A. Mason, Reinhard A. Schumacher, Marcel Adam Just. The neuroscience of advanced scientific concepts. npj Science of Learning, 2021; 6 (1) DOI: 10.1038/s41539-021-00107-6

https://medicalxpress.com/news/2021-10-ancient-brains-modern-physic...

Part3

Myth busted: General anesthesia just as safe as spinal anesthesia after broken hip surgery

New research shows that the rates of survival, functional recovery, and post-operative delirium are similar for patients whether they underwent general anesthesia or spinal anesthesia for hip fracture surgery. This work, from the largest randomized study ever conducted to compare the two anesthesia techniques, challenges common thinking that patients who get spinal anesthesia fare better. 

The study was published in the New England Journal of Medicine and presented at Anesthesiology 2021, the annual meeting of the American Society of Anesthesiologists (ASA).

During general anesthesia, inhaled and intravenous medications are used to make patients unconscious, which often requires temporary breathing tube placement to support the lungs during surgery. For spinal anesthesia, medications are used to numb the lower part of the body through an injection into the spinal column; while patients may receive sedation for comfort, they are typically able to breathe on their own during surgery and rarely require a breathing tube.

Most recent comparisons of general anesthesia versus spinal anesthesia come from studies that hadn't randomized their populations, some of which have suggested lower rates of cognitive and medical complications with spinal. While some patients may choose spinal anesthesia with the goal of avoiding complications, others opt for general anesthesia to avoid a spinal injection or out of fears of inadequate sedation during surgery.

Researchers enrolled 1,600 patients from 46 hospitals across the United States and Canada. The patients were all at least 50 years old, had broken a hip, and had previously been able to walk. Hip fractures are particularly worrisome among older populations, like the patients in the study, since they can lead to a loss of mobility, which is associated with doubling or even tripling the risk of near-term death. What set Neuman's study apart from past work in the subject area was that it randomly divided the enrolled patients into two equal groups: Those who were set to receive general anesthesia and those who were scheduled for spinal anesthesia. Approximately 800 patients were in each group. To get a fuller picture of the potential outcomes associated with each form of anesthesia, the researchers combined subsequent patient death rates and whether they regained the ability to walk, whether on their own or with a cane or walker. By 60 days after surgery, 18.5 percent of patients assigned to spinal anesthesia had either died or become newly unable to walk versus 18 percent of patients who received general anesthesia. When looking at mortality at 60 days alone, 3.9 percent of patients who received spinal anesthesia died versus 4.1 percent who got general anesthesia. Additionally, to examine how the different forms of anesthesia factored into potential cognitive complications, the researchers also examined post-operative delirium. Roughly 21 percent of patients assigned to spinal anesthesia experienced delirium versus 20 percent of those assigned to general anesthesia. "What our study offers is reassurance that general anesthesia can represent a safe option for hip fracture surgery for many patients," said Neuman. "This is information that patients, families, and clinicians can use together to make the right choice for each patient's personalized care."

 Spinal Anesthesia versus General Anesthesia for Hip Surgery in Older Adults, New England Journal of Medicine, 2021.

https://medicalxpress.com/news/2021-10-myth-anesthesia-safe-spinal-...

Lightning strikes may trigger short-term thinning in the ozone layer

Crack! Lightning strikes are bright and loud—violent enough to shake your bones and light up the sky. Now, a new study led by the University of Colorado Boulder suggests that these powerful events may also alter the chemistry of Earth's atmosphere, even affecting Earth's all-important ozone layer.

--

When breezy, wear masks outdoors to prevent coronavirus exposure

As the highly infectious delta variant of the coronavirus continues to spread  guidelines from experts recommend even the vaccinated wear masks indoors to prevent exposure and transmission.

However, it is less clear what people should do when outside.

In Physics of Fluids, researchers from the Indian Institute of Technology Bombay found when a person coughs outdoors, wind flowing in the same direction can propagate the virus faster over longer distances than in calm conditions.

The study is significant in that it points to the increased infection risk that coughing in the same direction as the wind could bring about. Based on the results, experts recommend wearing masks outdoors, particularly in breezy conditions.

Other guidelines, such as coughing in an elbow or turning the face away while coughing, should be followed to reduce transmission when socializing outdoors.

Most studies model cough flow using puffs of air or a simple pulsating profile. But a real cough is more complicated, exhibiting turbulent flow with prominent vortical structures swirling like mini whirlpools.

To investigate these vortices, the researchers used a large eddy simulation, a numerical model in computational fluid dynamics that simulates turbulence. They modeled cough jets in breezy conditions and in calm conditions representing a typical indoor environment.

These simulations show even a light breeze of about 5 mph extends effective social distancing by around 20%, from 3-6 feet to 3.6-7.2 feet, depending on cough strength. At 9-11 mph, spreading of the virus increases in distance and duration.

The researchers found the vortices enable bigger droplets to persist in the air longer than has been typically assumed, increasing the time it takes to adequately dilute the viral load in fresh air. As the cough jet evolves and spreads, it interacts with the wind flowing in the same direction, and the bigger infected droplets become trapped in the jet's vortices instead of falling relatively quickly to the ground under gravity.

The increase in residential time of some of the larger droplets will increase the viral load transmitting through the cough jet and, therefore, the chances of infection. Overall, the study highlights increased chances of infection in the presence of even a light breeze.

"Effect of co-flow on fluid dynamics of a cough jet with implications in spread of COVID-19" Physics of Fluids, aip.scitation.org/doi/10.1063/5.0064104

https://phys.org/news/2021-10-breezy-masks-outdoors-coronavirus-exp...

Photosynthesizing algae injected into the blood vessels of tadpoles supply oxygen to their brains

Leading a double life in water and on land, frogs have many breathing techniques—through the gills, lungs, and skin—over the course of their lifetime. Now German scientists have developed another method that allows tadpoles to "breathe" by introducing algae into their bloodstream to supply oxygen. The method developed, presented October 13 in the journal iScience, provided enough oxygen to effectively rescue neurons in the brains of oxygen-deprived tadpoles.

The algae actually produced so much oxygen that they could bring the nerve cells back to life. For many people, it sounds like science fiction, but after all, it's just the right combination of biological schemes and biological principles.

This is an idea to combine plant physiology with neuroscience: harnessing the power of photosynthesis to supply nerve cells with oxygen. The idea didn't seem far-fetched. In nature, algae live harmoniously in sponges, corals, and anemones, providing them with oxygen and even nutrients. Why not in vertebrates like frogs?

To explore the possibility, researchers injected green algae, Chlamydomonas renhardtii) or cyanobacteria (Synechocystis) into tadpoles' hearts. With each heartbeat, the algae inched through blood vessels and eventually reached the brain, turning the translucent tadpole bright green. Shining light on these tadpoles prompted both algae species to pump out oxygen to nearby cells.

After distributing algae to the brain, the researchers isolated the tadpole's head and placed it in an oxygen bubble bath with essential nutrients that would preserve the functioning of the cells, allowing the team to monitor neural activity and oxygen levels. As the researchers depleted oxygen from the bath, the nerves ceased firing and fell silent. However, illuminating the tadpole head restarted the neural activity within 15 to 20 minutes, which is about two times faster than replenishing the bath with oxygen without the algae. The revived nerves also performed as well or even better than before oxygen depletion, showing that the researchers' method was quick and efficient.

The team's next step is to see whether the injected algae can survive inside living tadpoles and continue oxygen production without causing an immune response that wreaks havoc on the animals.

iScience, Özugur et al.: "Green oxygen power plants in the brain rescue neuronal activity" www.cell.com/iscience/fulltext … 2589-0042(21)01126-3 , DOI: 10.1016/j.isci.2021.103158

https://phys.org/news/2021-10-photosynthesizing-algae-blood-vessels...

After two hours, sunscreen that includes zinc oxide loses effectiveness, becomes toxic: study

Sunscreen that includes zinc oxide, a common ingredient, loses much of its effectiveness and becomes toxic after two hours of exposure to ultraviolet radiation, according to a study by scientists.

The toxicity analysis involved zebrafish, which share a remarkable similarity to humans at the molecular, genetic and cellular levels, meaning many zebrafish studies are immediately relevant to people.

Findings were published recently in Photochemical & Photobiological Sciences.

Sunscreens are important consumer products that help to reduce UV exposures and thus skin cancer, but we do not know if the use of some sunscreen formulations may have unintended toxicity because of interactions between some ingredients and UV light.

And sunscreens containing inorganic compounds like zinc oxide or titanium dioxide, that block UV rays, are being marketed more and more heavily as safe alternatives to the organic small-molecule compounds that absorb the rays.

In the experiments conducted now, zinc oxide degraded the organic mixture and caused a greater than 80% loss in organic filter protection against ultraviolet-A rays, which make up 95% of the UV radiation that reaches the Earth. Also, the zinc-oxide-induced photodegradation products caused significant increases in defects to the zebrafish we used to test toxicity. That suggests zinc oxide particles are leading to degradants whose introduction to aquatic ecosystems is environmentally hazardous.

Aurora L. Ginzburg et al, Zinc oxide-induced changes to sunscreen ingredient efficacy and toxicity under UV irradiation, Photochemical & Photobiological Sciences (2021). DOI: 10.1007/s43630-021-00101-2

https://phys.org/news/2021-10-hours-sunscreen-zinc-oxide-effectiven...

Researchers engineer microorganisms to tackle PET plastic pollution

From overflowing landfills to floating garbage islands in the oceans to microplastics in remote wilderness areas, billions of tons of discarded plastic have created a global pollution crisis.

Did you know that  every one of us has a brain "fingerprint" and that this fingerprint changes over time?

RFusion: A Robot that Finds and Retrieves Missing Objects

So-called junk DNA plays critical role in mammalian development

Nearly half of our DNA has been written off as junk, the discards of evolution: Sidelined or broken genes, viruses that got stuck in our genome and were dismembered or silenced, none of it relevant to the human organism or human evolution.

But research over the last decade has shown that some of this genetic "dark matter" does have a function, primarily in regulating the expression of host genes—a mere 2% of our total genome—that code for proteins. Biologists continue to find whether these regulatory sequences of DNA play essential or detrimental roles in the body or are merely incidental, an accident that the organism can live without.

A new study explored the function of one component of this junk DNA, transposons, which are selfish DNA sequences able to invade their host genome. The study shows that at least one family of transposons—ancient viruses that have invaded our genome by the millions—plays a critical role in viability in the mouse, and perhaps in all mammals. When the researchers knocked out a specific transposon in mice, half their mouse pups died before birth.

This is the first example of a piece of "junk DNA" being critical to survival in mammals.

In mice, this transposon regulates the proliferation of cells in the early fertilized embryo and the timing of implantation in the mother's uterus. The researchers looked in seven other mammalian species, including humans, and also found virus-derived regulatory elements linked to cell proliferation and timing of embryo implantation, suggesting that ancient viral DNA has been domesticated independently to play a crucial role in early embryonic development in all mammals.

Andrew J. Modzelewski et al, A mouse-specific retrotransposon drives a conserved Cdk2ap1 isoform essential for development, Cell (2021). DOI: 10.1016/j.cell.2021.09.021

https://phys.org/news/2021-10-so-called-junk-dna-critical-role.html...