by Bob Yirka

A team of researchers from the University of California and Stanford University has found that the tendency to see people from different racial groups as interchangeable has a neuronal basis. In their paper published in Proceedings of the National Academy of Sciences, the group describes studies they conducted with volunteers and what they found.

One often-heard phrase connected with racial profiling is “they all look the same to me,” a phrase usually perceived as racist. It implies that people of one race have difficulty discerning the facial characteristics of people of another race. In this new effort, the researchers conducted experiments to find out if this is valid—at least among one small group of young, white men.

In the first experiment, young, white male volunteers looked at photographs of human faces, some depicting black people, others white, while undergoing an fMRI scan. Afterward, the researchers found that the part of the brain involved in facial recognition activated more for white faces than it did for black faces.

In the second experiment, the same volunteers looked at photographs of faces that had been doctored to make the subjects appear more alike, regardless of skin color. The researchers report that the brains of the volunteers activated when dissimilarities were spotted, regardless of skin color, though it was more pronounced when the photo was of a white face.

In a third series of experiments, the volunteers rated how different they found faces in a series of photographs or whether they had seen a given face before. The researchers report that the volunteers had a tendency to rate the black faces as more similar to one another than the white faces. And they found it easier to tell if they had seen a particular white face before.

The researchers suggest that the results of their experiments indicate a neural basis that makes it more difficult for people to see differences between individuals of other races. They note that they did account for social contexts such as whether the volunteers had friends and/or associates of other races. They suggest that more work is required to determine if such neuronal biases can be changed based on social behavior.

Brent L. Hughes et al. Neural adaptation to faces reveals racial outgroup homogeneity effects in early perception, Proceedings of the National Academy of Sciences (2019). DOI: 10.1073/pnas.1822084116

https://medicalxpress.com/news/2019-07-neuronal-alike.html

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Kumar Alagramam. PhD, Case Western Reserve University

The ability to hear depends on proteins to reach the outer membrane of sensory cells in the inner ear. But in certain types of hereditary hearing loss, mutations in the protein prevent it from reaching these membranes. Using a zebrafish model, researchers at Case Western Reserve University School of Medicine have found that an anti-malarial drug called artemisinin may help prevent hearing loss associated with this genetic disorder.

In a recent study, published in the Proceedings of the National Academy of Sciences (PNAS), researchers found the classic anti-malarial drug can help sensory cells of the inner ear recognize and transport an essential protein to specialized membranes using established pathways within the cell.

The sensory cells of the inner ear are marked by hair-like projections on the surface, earning them the nickname “hair cells.” Hair cells convert sound and movement-induced vibrations into electrical signals that are conveyed through nerves and translated in the brain as information used for hearing and balance.

The mutant form of the protein–clarin1–render hair cells unable to recognize and transport them to membranes essential for hearing using typical pathways within the cell. Instead, most mutant clarin1 proteins gets trapped inside hair cells, where they are ineffective and detrimental to cell survival. Faulty clarin1 secretion can occur in people with Usher syndrome, a common genetic cause of hearing and vision loss.

The study found artemisinin restores inner ear sensory cell function—and thus hearing and balance—in zebrafish genetically engineered to have human versions of an essential hearing protein.

Senior author on the study, Kumar N. Alagramam, the Anthony J. Maniglia Chair for Research and Education and associate professor at Case Western Reserve University School of Medicine Department of Otolaryngology at University Hospitals Cleveland Medical Center, has been studying ways to get mutant clarin1 protein to reach cell membranes to improve hearing in people with Usher syndrome.

“We knew mutant protein largely fails to reach the cell membrane, except patients with this mutation are born hearing,” Alagramam said. “This suggested to us that, somehow, at least a fraction of the mutant protein must get to cell membranes in the inner ear.”

Alagramam’s team searched for any unusual secretion pathways mutant clarin1 could take to get to hair cell membranes. “If we can understand how the human clarin1 mutant protein is transported to the membrane, then we can exploit that mechanism therapeutically,” Alagramam said.

For the PNAS study, Alagramam’s team created several new zebrafish models. They swapped the genes encoding zebrafish clarin1 with human versions—either normal clarin1, or clarin1 containing mutations found in humans with a type of Usher syndrome, which can lead to profound hearing loss.

“Using these ‘humanized’ fish models,” Alagramam said, “we were able to study the function of normal clarin1 and, more importantly, the functional consequences of its mutant counterpart. To our knowledge, this is the first time a human protein involved in hearing loss has been examined in this manner.”

Zebrafish offer several advantages to study hearing. Their larvae are transparent, making it easy to monitor inner ear cell shape and function. Their genes are also nearly identical to humans—particularly when it comes to genes that underlie hearing. Replacing zebrafish clarin1 with human clarin1 made an even more precise model.

The researchers found the unconventional cellular secretion pathway they were looking for by using florescent labels to track human clarin1 moving through zebrafish hair cells. The mutated clarin1 gets to the cell membrane using proteins and trafficking mechanisms within the cell, normally reserved for misfolded proteins “stuck” in certain cellular compartments.

“As far as we know, this is the first time a human mutant protein associated with hearing loss has been shown to be ‘escorted’ by the unconventional cellular secretion pathway,” Alagramam said. “This mechanism may shed light on the process underlying hearing loss associated with other mutant membrane proteins.”

The study showed the majority of mutant clarin1 gets trapped inside a network of tubules within the cell analogous to stairs and hallways helping proteins, including clarin1, get from place to place. Alagramam’s team surmised that liberating the mutant protein from this tubular network would be therapeutic and tested two drugs that target it: thapsigargin (an anti-cancer drug) and artemisinin (an anti-malarial drug).

The drugs did enable zebrafish larvae to liberate the trapped proteins and have higher clarin1 levels in the membrane; but artemisinin was the more effective of the two. Not only did the drug help mutant clarin1 to reach the membrane, hearing and balance functions were better preserved in zebrafish treated with the anti-malarial drug than untreated fish.

In zebrafish, survival depends on normal swim behavior, which in turn depends on balance and the ability to detect water movement, both of which are tied to hair cell function. Survival rates in zebrafish expressing the mutant clarin1 jumped from 5% to 45% after artemisinin treatment.

“Our report highlights the potential of artemisinin to mitigate both hearing and vision loss caused by clarin1 mutations,” Alagramam said. “This could be a re-purposable drug, with a safe profile, to treat Usher syndrome patients.”

Alagramam added that the unconventional secretion mechanism and the activation of that mechanism using artemisinin or similar drugs may also be relevant to other genetic disorders that involve mutant membrane proteins aggregating in the cell’s tubular network, including sensory and non-sensory disorders.

Gopal SR, et al. “Unconventional secretory pathway activation restores hair cell mechanotransduction in an USH3A model.” PNAS.

Drug to treat malaria could mitigate hereditary hearing loss

By Knvul Sheikh

As our devices get smaller and more sophisticated, so do the materials we use to make them. That means we have to get up close to engineer new materials. Really close.

Different microscopy techniques allow scientists to see the nucleotide-by-nucleotide genetic sequences in cells down to the resolution of a couple atoms as seen in an atomic force microscopy image. But scientists at the IBM Almaden Research Center in San Jose, Calif., and the Institute for Basic Sciences in Seoul, have taken imaging a step further, developing a new magnetic resonance imaging technique that provides unprecedented detail, right down to the individual atoms of a sample.

The technique relies on the same basic physics behind the M.R.I. scans that are done in hospitals.

When doctors want to detect tumors, measure brain function or visualize the structure of joints, they employ huge M.R.I. machines, which apply a magnetic field across the human body. This temporarily disrupts the protons spinning in the nucleus of every atom in every cell. A subsequent, brief pulse of radio-frequency energy causes the protons to spin perpendicular to the pulse. Afterward, the protons return to their normal state, releasing energy that can be measured by sensors and made into an image.

But to gather enough diagnostic data, traditional hospital M.R.I.s must scan billions and billions of protons in a person’s body, said Christopher Lutz, a physicist at IBM. So he and his colleagues decided to pack the power of an M.R.I. machine into the tip of another specialized instrument known as a scanning tunneling microscope to see if they could image individual atoms.


Four M.R.I. scans, combined, of a single titanium atom, showing the magnetic field of the atom at different strengths.CreditWillke et al.

The tip of a scanning tunneling microscope is just a few atoms wide. And it moves along the surface of a sample, it picks up details about the size and conformation of molecules.

The researchers attached magnetized iron atoms to the tip, effectively combining scanning-tunneling microscope and M.R.I. technologies.

When the magnetized tip swept over a metal wafer of iron and titanium, it applied a magnetic field to the sample, disrupting the electrons (rather than the protons, as a typical M.R.I. would) within each atom. Then the researchers quickly turned a radio-frequency pulse on and off, so that the electrons would emit energy that could be visualized. The results were described Monday in the journal Nature Physics.

“It’s a really magnificent combination of imaging technologies,” said A. Duke Shereen, director of the M.R.I. Core Facility at the Advanced Science Research Center in New York. “Medical M.R.I.s can do great characterization of samples, but not at this small scale.”

The atomic M.R.I. provides subångström-level resolution, meaning it can distinguish neighboring atoms from one another, as well as reveal which types of atoms are visible based on their magnetic interactions.

“It is the ultimate way to miniaturization,” Dr. Lutz said. He hopes the new technology could one day be used to design atomic-scale methods of storing information, for quantum computers.

Current transistors are thousands of atoms wide and need to switch on and off to store a single bit of information in a computer. The ability to corral individual atoms could drastically increase computing power and enable researchers to tackle complex calculations such as predicting weather patterns or diagnosing illnesses with artificial intelligence.

Moving an atom from one location to another in a composite could also change and lead to the development of new ones.

The technique might also help scientists study how proteins fold and develop new drugs that bind to specific curves in a biological structure.

“We can now see something that we couldn’t see before,” Dr. Lutz said. “So our imagination can go to a whole bunch of new ideas that we can test out with this technology.”

«We first did not believe it was true,» researchers Eva Fuglei says about the amazing run of the adventurous Arctic fox.

The animal that was carrying a satellite-tracked necklace set out from the Spitsbergen island on 26th March 2018. After 21 days, it arrived in Greenland. But it did not stop there. The fox subsequently continued its Arctic odyssey all the way to Ellesmere Island in Canada.

The distance of 3,506 km was completed in only 76 days, the Norwegian Polar Research Institute says. The average daily distance of the fox was 46 km. At most, the animal ran as much as 155 km per day.

«This is the quickest speed ever registered with an Arctic fox,» Fuglei says in a comment.

It used the Arctic ice as a trans-continental bridge, the researcher says.

Fuglei, a researcher at the Polar Research Institute, has conducted the study together with Arnaud Tarroux from the Norwegian Institute of Nature Research (NINA), and the results were recently published in an article in the Polar Research magazine.

It is the first ever study that in detail shows how an Arctic fox wanders between continents and different Arctic ecosystems, and the first ever documented migration from Svalbard to Canada.

The animal had an impressive speed, the researchers underline. It first crossed the polar ice between Svalbard and Greenland and then passed great glaciers before it again made it across the ice to Ellesmere Island.

The destiny of the small fox in Canada will be unknown to the researchers as the satellite transmitter stopped working in February this year. «But it will definitely have to change its food habits,» says Eva Fuglei. The Arctic fox population in Ellesmere Island eats mostly lemmings, while the Svalbard foxes find food in marine environments.

It is well known to researchers that Arctic foxes migrate across the Arctic, but Eva Fuglei and the Polar Reseach Institute are baffled by the long and quick run of the little super-fox.

Previously, Arctic fox populations migrated also between Iceland, Jan Mayen and other parts of the Arctic. But these populations are now isolated as the polar ice has vanished.

The ice has always provided animals with a platform for food and migration. However, with the warmer global climate and the melting Arctic ice life conditions for animals are under change.

https://thebarentsobserver.com/en/ecology/2019/06/arctic-fox-across-polar-ice-makes-record-run-svalbard-canada-25-month

Calgary student Nora Keegan has been studying decibel levels in hand dryers since she was 9 years old.

Children who say hand dryers “hurt my ears” are correct.

A new research paper by that very title has just been published in Paediatrics & Child Health, Canada’s premier peer-reviewed pediatric journal. And the researcher, 13-year-old Nora Keegan, has been studying the issue since she was nine years old.

“In Grade 4, I noticed that my ears kind of hurt after the hand dryer,” Keegan told the Calgary Eyeopener. “And then later, at the start of Grade 5, I also noticed that my ears were hurting after I used the hand dryer. So then I decided to test it to see if they were dangerous to hearing, and it turns out they are.”

Keegan used a decibel meter, and measured the noise at different heights and different distances from the wall.

“I thought it would be good to have a lot of children’s heights and also women’s height and men’s height, and then I measured 18 inches from the wall, which is the industry standard. And I also measured 12 inches from the wall since I thought the children might stand closer because their hands and arms are shorter.”

She discovered something even more alarming.

“And then one time I was testing on the decibel meter and my hand accidentally passed into the airstream flow, and the decibels shot up a lot,” she said. “So then I decided to make that another part of my testing method. So I also measured with hands in the air flow and without hands in the air.”

Keegan discovered that the sound was even louder with the hands in the airflow.

“And it was also really loud at children’s heights and manufacturers don’t measure for children’s height as much either.”

Eventually, Keegan determined that there are two models in particular that are harmful for children’s ears: the Dyson and XCelerator, which both operate at about 110 decibels. Health Canada has regulated that no toys operate at more than 100 decibels.

“So this is very loud, around the level of a rock concert,” Keegan said. “And this is also louder than Health Canada’s regulation for children’s toys, as they know that at this level it poses a danger to children’s hearing.”

Children have smaller ear canals and more sensitive follicles. And they tend to stand closer to the dryers because their bodies are smaller and their arms are shorter.

These are all things Keegan started documenting in a series of research projects.

“So it started out as a school science fair in Grade 5. And then I really enjoyed it, and I thought I could do more with it,” she said. “So then I continued working on it in Grade 6, and then Grade 7, I started writing the paper, and it just got published now in Paediatrics & Child Health.”

Keegan is a Grade 8 student at Branton Junior High School in Calgary. The full title of her paper is, “Children who say hand dryers ‘hurt my ears’ are correct: A real-world study examining the loudness of automated hand dryers in public places.”

But the young scientist, who says she hopes to have a career as a marine biologist, isn’t stopping with this personal success. She wants to do something about the problem.

By experimenting with different materials, she’s made a model that reduces the noise by 11 decibels.

Keegan’s synthetic air filter, which looks like a fuzzy handbag, absorbs the sound waves.

“The air comes down further so even though your hands still reach the airflow, then your ears are a greater distance from where the air comes out.”

Keegan conducted an informal test of the air filter at her school.

“I couldn’t really find a way to test it, but I installed it in my school’s washroom and I found that it didn’t (heat up). People seemed to enjoy it and it didn’t seem to have a problem.”

Keegan said she hasn’t tried to do anything official with the air filter — yet.

“I think I might go and talk to the manufacturers and also I might go and talk to Health Canada because even though this is a study, it’s still only one study. So it’d be better if they tested more hand dryers and found more about that loudness of hand dryers.”

Keegan assessed 44 different hand dryers, from places that kids would be using them all over Calgary — arenas, restaurants, schools, libraries and shopping malls.

https://www.cbc.ca/news/canada/calgary/calgary-student-nora-keegan-hand-dyer-research-decibel-1.5185853?utm_source=Nature+Briefing&utm_campaign=34225bcef1-briefing-dy-20190701&utm_medium=email&utm_term=0_c9dfd39373-34225bcef1-44039353


A Soviet cow-fattening complex pictured in 1982.Credit: Nikolai Akimov/TASS

by Quirin Schiermeier

The collapse of the Soviet Union in 1991 led to a huge drop in greenhouse-gas emissions because the resulting economic crisis meant many people stopped eating meat.

Meat from domestic livestock farming was a main food staple during communist rule in the region. In 1990, Soviet citizens each consumed an average 32 kilograms of beef a year — 27% more than Western Europeans and four times more than the global average at the time.

But meat demand and livestock production in the region fell drastically when the prices of everyday consumer products soared and the purchasing power of the rouble dwindled in the post-communist economic crisis. An estimated one-third of late-Soviet cropland has been abandoned since.

These changes in the food and agriculture system in the former Soviet nations resulted in a net reduction of 7.6 billion tonnes of greenhouse gases in carbon dioxide equivalent from 1992 to 2011, researchers find from an analysis of data on livestock consumption and international trade1 (see ‘Soviet shocks’). The drop is equivalent to one-quarter of CO2 emissions from Amazon deforestation over the same period. Russia currently emits about 2.5 billion tonnes of greenhouse gases (CO2 equivalent) per year.

The figure considers emissions that result from domestic production of livestock and imported livestock, as well as carbon locked in soils and plants on abandoned Soviet cropland.

“There was a large drop in industrial production and emissions after the collapse of the Soviet Union, so it should be no surprise the same happened with food consumption and production,” says Glen Peters, a carbon-budget specialist at the Center for International Climate Research in Oslo, who was not involved in the analysis. “The study highlights the potential for carbon uptake in the former Soviet Union but also the risks to that carbon being released if agricultural production returns.”

Today, animal agriculture is responsible for 14.5% of human-caused greenhouse-gas emissions globally. Beef is the most emissions-intensive food because pastures are often created by clearing forests and savannahs.

Meat consumption — especially beef — and land-use changes in Russia and central Asia are a widely overlooked factor in calculations of greenhouse-gas emissions from land around the globe, says study author Florian Schierhorn at the Leibniz Institute of Agricultural Development in Transition Economies in Halle, Germany.

Trends in international trade suggest that emissions associated with meat consumption are on the rise again: Russia has over the past decade become a top destination for beef exported mainly from South America.

doi: 10.1038/d41586-019-02024-6

References
1. Schierhorn, F. et al. Environ. Res. Lett. 14, 065009 (2019).

https://www.nature.com/articles/d41586-019-02024-6?utm_source=Nature+Briefing&utm_campaign=34225bcef1-briefing-dy-20190701&utm_medium=email&utm_term=0_c9dfd39373-34225bcef1-44039353


Villagers waiting to vote in Kenya. In this queue at a polling station, there are both barefoot and shod individuals. Holowka et al.5 studied people in Kenya and the United States who either are usually barefoot or usually wear shoes. The authors investigated whether the formation of thick patches of skin called calluses, which are usually thicker and harder in people who are normally barefoot than in shod individuals, affects foot sensitivity.Credit: Roberto Schmidt/AFP/Getty

By approximately 6 million years ago1,2, our hominin ancestors walked upright. Since then, ancient hominins, and eventually humans, have used their feet as their only point of contact with the ground. Evidence suggests that, long after our species evolved about 200,000 years ago to become anatomically modern humans (our current form)3, some people began to wear shoes for protection and for many other reasons — beginning about 40,000 years ago4. But wouldn’t it be great if foot protection existed that could preserve our sensation (termed tactile sensitivity) of the ground beneath our feet? Writing in Nature, Holowka et al.5 report that thick patches of foot skin, termed calluses, do just that. The authors reached this conclusion by studying callus thickness and hardness, plus foot sensitivity, in individuals in Kenya and the United States who usually either wear shoes or go barefoot.

Holowka and colleagues measured callus thickness using ultrasound. They report that people who were normally barefoot had calluses that were approximately 30% thicker than those of people who typically wore shoes. It could be assumed that thicker calluses provide more protection than thinner ones, all else being equal. But is all else indeed equal? To find out, the authors quantified the mechanical properties of foot soles using a device called a Shore durometer. This tool is commonly used in the footwear industry, and measures foot resistance to an indentation caused by the apparatus. The authors’ results show that, compared with skin on the feet of those who normally wore shoes, the skin of barefoot individuals was approximately 30% harder. This thicker, harder skin presumably protects their feet just like a shoe’s sole.

Our feet are remarkably sensitive, enabling pleasant sensations such as the feeling when walking barefoot on a beach, but also the experience of pain when stepping on a sharp rock. This sensitivity is useful because our body’s nerves use such information to fine-tune our posture and gait, in a similar way to how our sensitive fingertips enable us to precisely manipulate objects. As part of the system that aids this tactile sensitivity, a variety of mechanoreceptors in our skin sense mechanical stimuli such as pressure. If these receptors don’t work normally, as can occur in disease6 or during experimental manipulation7, people can have problems with their balance or gait8.

Using a device called a vibration exciter, Holowka and colleagues assessed the sensitivity of two types of mechanoreceptor, known as Meissner and Pacinian corpuscles, in their volunteers. These mechanoreceptors respond to high-frequency pressure stimulations (at 5–50 and 100–300 hertz, respectively) that occur when walking and running, especially when the foot strikes the ground. Holowka and colleagues’ key discovery is probably unexpected, given that one might predict that a thick layer of skin would be a barrier to the transmission of stimuli: mechanoreceptor sensitivity is not lower in habitually barefoot people than in people who usually wear shoes.

Barefoot walking with thick calluses is our biologically normal condition, and people who usually walk barefoot experience few problems doing so9,10, as I have also observed in my research in India11,12. Walkers who are habitually barefoot report no pain when walking on most terrains that shod walkers would find painful to walk on barefoot. However, habitually barefoot walkers might be at a higher risk of traumatic injury, given that shoes can offer better protection than can calluses13. Nevertheless, barefoot-walkers’ feet might be generally healthier than those of habitually shod people9, and foot problems such as bunions and fallen arches are rare in people who seldom wear shoes.

Should we now bin our shoes? Well, maybe not. Shoes can help people who have foot conditions14, and can also boost athletic performance15. In everyday life, shoes can keep our feet warm, and offer more protection than calluses can. Therefore, what kind of shoes we should wear becomes the more pressing question.

Holowka and colleagues argue that thick calluses preserve sensitivity because their hardness enables mechanical stimuli from the ground to be transmitted, with little dampening, to deep layers of the skin in which the key mechanoreceptors are located. If so, shoes with hard soles should be predicted to do the same job as calluses. Indeed, the hard-soled shoes used by drivers competing in Formula 1 races provide even greater than normal sensitivity at high frequencies of vibration16.

More research will be needed to fully understand the effect of shoe soles on gait. Humans are not like machines, in which just one variable at a time can be studied. Human movement is a complex, dynamic system, and changing even one variable, such as shoe-sole stiffness, will probably trigger other physiological and behavioural changes. For example, running when using cushioned soles, compared with running barefoot, triggers changes in how the foot makes contact with the ground (called the strike pattern)17, and also causes the arch of the foot to behave more stiffly18.

Holowka et al. conducted an experiment using a treadmill apparatus to quantify impact forces, which are the forces that the foot encounters immediately after it strikes the ground. They found that even if uncushioned shoes were used to mimic a callus-like sole, these shoes did not exactly mirror the effect of calluses during foot strike. Compared with their observations of unshod individuals, such footwear led to a slower rise in the impact force and a higher impulse (the product of the force and duration of the impact phase, which is when the foot hits the ground and slows abruptly).

It makes sense that preserving foot sensitivity is useful, especially if maintaining stability is challenging. This is true for gymnasts and also for older people, in whom faculties such as vision, balance and foot sensitivity decline naturally with age. Shoes with hard soles might therefore be a good idea for such individuals. Indeed, wearing hard-soled shoes can reduce the risk of older people falling19. Holowka and colleagues’ work helps to explain why this is so. Although this mystery has been solved, much remains to be discovered about what affects how humans walk.

doi: 10.1038/d41586-019-01953-6
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5. Holowka, N. B. et al. Nature https://doi.org/10.1038/s41586-019-1345-6 (2019).

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8. Alfuth, M. & Rosenbaum, D. Footwear Sci. 4, 1–22 (2012).

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10. Sim-Fook, L. & Hodgson, A. J. Bone Joint Surg. Am. 40, 1058–1062 (1958).

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12. Willems, C., Stassijns, G., Cornelis, W. & D’Août, K. Am. J. Phys. Anthropol. 162, 782–793 (2017).

13. Engle, E. T. & Morton, D. J. J. Bone Joint Surg. 13, 311–318 (1931).

14. Bus, S. A. et al. Diabetes/Metab. Res. Rev. 32 (suppl.), 99–118 (2016).

15. Hoogkamer, W. et al. Sports Med. 48, 1009–1019 (2018).

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18. Kelly, L. A., Lichtwark, G. A., Farris, D. J. & Cresswell, A. J. R. Soc. Interface 13, 20160174 (2016).

19. Aboutorabi, A. et al. Prosthet. Orthot. Int. 40, 170–181 (2016).

https://www.nature.com/articles/d41586-019-01953-6