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Scientists learn why nacre is nature's toughest material

Material Science
© Evan Dougherty, Michigan Engineering
Jiseok Gim, materials science and engineering PhD candidate, demonstrates loading a sample into the JEOL 3100R05 electron microscope in the Michigan Center for Materials.
Ann Arbor — Nacre, the rainbow-sheened material that lines the insides of mussel and other mollusk shells, is known as nature's toughest material. Now, a team of researchers led by the University of Michigan has revealed precisely how it works, in real time.

More commonly known as mother-of-pearl, nacre's combination of hardness and resilience has mystified scientists for more than 80 years. If humans could mimic it, it could lead to a new generation of ultra-strong synthetic materials for structures, surgical implants and countless other applications.

"We humans can make tougher materials using unnatural environments, for example extreme heat and pressure. But we can't replicate the kind of nano-engineering that mollusks have achieved. Combining the two approaches could lead to a spectacular new generation of materials, and this paper is a step in that direction," said Robert Hovden, U-M assistant professor of materials science and engineering.

Researchers have known the basics of nacre's secret for decades — it's made of microscopic "bricks" of a mineral called aragonite, laced together with a "mortar" made of organic material. This bricks-and-mortar arrangement clearly lends strength, but nacre is far stronger than its materials suggest.

Hovden's team, which included U-M materials science graduate research assistant Jiseok Gim as well as geochemists from Australia's Macquarie University and elsewhere, worked together to crack the mystery.

Info

Mercury in fossilised ferns revealed as hidden driver in mass extinctions

Mutated Ferns
© GEUS
Mutated ferns point to a new culprit in prehistoric mass extinctions, researchers say.
Bad news loves company. Researchers have discovered that it wasn't just erupting volcanoes, massive amounts of carbon dioxide, oceans full of sulphuric acid, runaway global warming and a thinning ozone layer that caused the end-Triassic mass extinction 201 million years ago.

It was also large quantities of lethal mercury causing plant life to mutate and die.

Four out of the five mass extinctions that occurred over the past 600 million years have been linked to huge and prolonged bursts of volcanic activity.

In the case of the Triassic event - which saw the end of an estimated 40% of land animal genera and 30% of ocean-dwelling groups - there is ample evidence that volcanoes sprang to life across an area known as the Central Atlantic Magmatic Province (CAMP) 100,000 years before the great dying began. It continued, sporadically, for another 700,000.

Such a profound upheaval causes substantial environmental disruption - including long-lasting spikes in carbon dioxide and sulphur combinations that have been regularly and reliably associated with high levels of animal and plant deaths.

Now, however, scientists led by Sofie Lindström of the Geological Survey of Denmark and Greenland have identified another nasty: pulsed elevated concentrations of mercury in the ocean and the soil.

Microscope 2

Super-precise! New CRISPR tool may tackle genetic diseases

old CRISPR
© Juan Gaertner/SPL
A new gene-editing tool called prime editing allows for greater precision and control over DNA edits compared to the popular CRISPR-Cas9 system (pictured).
The system allows researchers more control over DNA changes, potentially opening up conditions that have challenged gene-editors.

For all the ease with which the wildly popular CRISPR-Cas9 gene-editing tool alters genomes, it's still somewhat clunky and prone to errors and unintended effects. Now, a recently developed alternative offers greater control over genome edits — an advance that could be particularly important for developing gene therapies.

The alternative method, called prime editing, improves the chances that researchers will end up with only the edits they want, instead of a mix of changes that they can't predict. The tool, described in a study published on 21 October in Nature, also reduces the 'off-target' effects that are a key challenge for some applications of the standard CRISPR-Cas9 system. That could make prime-editing-based gene therapies safer for use in people.

The tool also seems capable of making a wider variety of edits, which might one day allow it to be used to treat the many genetic diseases that have so far stymied gene-editors. David Liu, a chemical biologist at the Broad Institute of MIT and Harvard in Cambridge, Massachusetts and lead study author, estimates that prime editing might help researchers tackle nearly 90% of the more than 75,000 disease-associated DNA variants listed in ClinVar, a public database developed by the US National Institutes of Health.

Galaxy

Spotting a wormhole: Physicists propose technique for detecting spacetime bridges

wormhole black hole spacetime bridge
In a theoretical study, physicists propose that perturbations in the orbit of stars near supermassive black holes could be used to detect wormholes.

A new study outlines a method for detecting a speculative phenomenon that has long captured the imagination of sci-fi fans: wormholes, which form a passage between two separate regions of spacetime.

Such pathways could connect one area of our universe to a different time and/or place within our universe, or to a different universe altogether.

Whether wormholes exist is up for debate. But in a paper published on October 10, 2019, in Physical Review D, physicists describe a technique for detecting these bridges.

Brain

Scientists develop control system designed to teach robotic wheelchairs to understand user intent

Person in wheelchair
© CC0
Scientists at the National Research Nuclear University MEPhI (NRNU MEPhI) have developed a decomposition method for multi-channel control systems based on an extended BCI designed to help robotic wheelchair users.

The results of the study were published in the book Biologically Inspired Cognitive Architectures Meeting.

The use of a robotic wheelchair with a multi-channel control system is crucial for people with highly reduced mobility. Often, patients are only able to perform small hand gestures, give voice commands or project "mental images".

Different control channels have their drawbacks. For example, a traditional joystick controller may not be suitable for people with minimal motor activity. Therefore, a voice control channel, a gesture control channel, and a channel based on BCI (brain-computer interface) are also in demand. The combination of all these channels is called enhanced BCI.

Info

New study expands understanding of the 'gut-brain axis'

Gut Bacteria
© MARTIN-DM / GETTY IMAGES
Targeting bacteria in the intestine may be a strategy for addressing depression and anxiety.
Scientists have discovered that resident bacteria of the intestine, collectively known as the gut microbiome, can influence the ability to overcome fear.

The finding, published in the journal Nature, could one day help people with post-traumatic stress disorder. It also dramatically expands understanding of the "gut-brain" axis, which is known to have a hand in depression, anxiety and autism.

The researchers, led by immunologist David Artis at Cornell University in New York, US, started by putting the frighteners on a bunch of mice - some healthy and others treated with antibiotics to wipe out their gut bacteria.

They followed standard procedure for getting mice scared. They put the critters in a special chamber where a tone sounded for 30 seconds. When the tone stopped the mice got an electric shock to their feet through the floor.

As you might expect, it wasn't long before they started freezing with fear as soon as they heard the tone - your paradigm case of Pavlovian conditioning.

Fortunately for mice, however, fear can be unlearned.

Gear

Google AI touts a 'quantum supremacy' experiment using a programmable superconducting processor

Sycamore processor mounted in the cryostat
© Erik Lucero, Research Scientist and Lead Production Quantum Hardware
Left: Artist's rendition of the Sycamore processor mounted in the cryostat. (Forest Stearns, Google AI Quantum Artist in Residence) Right: Photograph of the Sycamore processor.
Physicists have been talking about the power of quantum computing for over 30 years, but the questions have always been: will it ever do something useful and is it worth investing in? For such large-scale endeavors it is good engineering practice to formulate decisive short-term goals that demonstrate whether the designs are going in the right direction. So, we devised an experiment as an important milestone to help answer these questions. This experiment, referred to as a quantum supremacy experiment, provided direction for our team to overcome the many technical challenges inherent in quantum systems engineering to make a computer that is both programmable and powerful. To test the total system performance we selected a sensitive computational benchmark that fails if just a single component of the computer is not good enough.

Today we published the results of this quantum supremacy experiment in the Nature article, "Quantum Supremacy Using a Programmable Superconducting Processor". We developed a new 54-qubit processor, named "Sycamore", that is comprised of fast, high-fidelity quantum logic gates, in order to perform the benchmark testing. Our machine performed the target computation in 200 seconds, and from measurements in our experiment we determined that it would take the world's fastest supercomputer 10,000 years to produce a similar output.


Comment: Watch their commercial:



Comment: These Google AI scientists seem to leave out the biggest reason their project is even being funded - and how it is likely to be implemented: for the technocratic subjugation of the domestic populace, and the powering of war against "adversaries" abroad; "and if a few cool quantum batteries can be produced for regular industrial consumption, well, that's fine too."


Wolf

Museums are sexist! Study suggests collectors prefer male specimens over female

museum collection

Researchers found a clear bias towards male specimens in museum collections of animals and birds dating back decades.
Museum collections of birds and mammals may be disproportionately skewed to favour males, even if female members of the species outnumber males in the wild, according to research published Wednesday.

Natalie Cooper, a researcher in the department of life sciences at the Natural History Museum in London, and her colleagues analysed the sex of almost 2.5 million specimens from five international collections, some dating back over a century.

Although as many as half of the bird specimens were not labelled by sex, of the ones that were, only 40 percent were female. Female mammals represented 48 percent of the collections identified by sex.


Comment: 48 percent? Someone better get over to their local museum and protest straight away. This is unacceptable!


"We suspected that some bias towards males would be found because science is done by people, and people have inherent biases towards males," Cooper told AFP.

What surprised the researcher, though, was that there was no change in the ratios from collections dating back 130 years to more recent collections.

Comment: Gender is not a social construct -- at least when it comes to museum specimens.


Cow

Study finds painting 'zebra stripes' on cows wards off biting flies

cow stripes biting flies
© Kojima et al./PLoS One
Painting 'zebra stripes' on cattle resulted in fewer biting fly attacks
Ranchers might want to consider painting "zebra stripes" on their livestock. According to a new study published in PLoS ONE, the measure reduces the number of biting flies on cows by more than half.

Biting flies are one of the great banes of cows worldwide. The irritating insects cause cows to graze less, eat less, sleep less, and also to bunch together into tightly clumped groups, which stresses the animals and leads to more injuries. The damage done by biting flies equates to roughly $2.2 billion in yearly economic losses for the U.S. cattle industry.

Seeking a potential solution to this situation, a team of Japanese researchers cleverly applied lessons from research on zebras. Animal scientists have long pondered the function of zebras' distinct stripes, and a growing consensus now suggests that they deter insects, possibly by confusing bugs' motion detection systems that control approach and landing.

Saturn

Astronomers have spotted a new type of storm on Saturn

Saturn storms
© JPL-CALTECH/NASA, SSI
Until now, astronomers have only seen Saturn ravaged by small storms that last days or enormous Great White Spots that last months (a Great White Spot that raged in 2010 and 2011 pictured). Now, astronomers have identified a third, midsize kind of storm activity on the gas giant.
Saturn saw some weird weather last year.

Telescope images have revealed a newfound type of storm activity that raged near Saturn's North Pole in 2018, researchers report online October 21 in Nature Astronomy.

Until now, astronomers had seen only two kinds of Saturnian storms: relatively small storms about 2,000 kilometers across that appear as bright clouds for a few days and Great White Spots that are 10 times as large and last for months (SN: 4/14/15). The newly spotted weather disturbance was a series of four midsize storms. Each was several thousand kilometers across and lasted between about 1.5 weeks and about seven months.

Saturnian storms are thought to originate in water clouds hundreds of kilometers below the planet's visible upper cloud cover. Studying such storms can offer a window into deep atmospheric goings-on that aren't directly observable, says Agustín Sánchez-Lavega, who studies planetary atmospheres at the University of the Basque Country in Bilbao, Spain.

Comment: Some other recent discoveries about Saturn include: