A new design for an artificial eyeball (illustrated) could someday give keen eyesight to androids, or be used as a high-tech prosthetic.


The design for a new artificial eye (illustrated) is based on the structure of the human eye. At the back of the eyeball, a synthetic retina is embedded with nanoscale light sensors. Those sensors measure light that passes through the lens at the front of the eye. Wires attached to the back of the retina ferry signals from those sensors to external circuitry for processing, similar to the way nerve fibers connect the eyeball to the brain.

By Maria Temming

Scientists can’t yet rebuild someone with bionic body parts. They don’t have the technology. But a new artificial eye brings cyborgs one step closer to reality.

This device, which mimics the human eye’s structure, is about as sensitive to light and has a faster reaction time than a real eyeball. It may not come with the telescopic or night vision capabilities that Steve Austin had in The Six Million Dollar Man television show, but this electronic eyepiece does have the potential for sharper vision than human eyes, researchers report in the May 21 Nature.

“In the future, we can use this for better vision prostheses and humanoid robotics,” says engineer and materials scientist Zhiyong Fan of the Hong Kong University of Science and Technology.

The human eye owes its wide field of view and high-resolution eyesight to the dome-shaped retina — an area at the back of the eyeball covered in light-detecting cells. Fan and colleagues used a curved aluminum oxide membrane, studded with nanosize sensors made of a light-sensitive material called a perovskite (SN: 7/26/17), to mimic that architecture in their synthetic eyeball. Wires attached to the artificial retina send readouts from those sensors to external circuitry for processing, just as nerve fibers relay signals from a real eyeball to the brain.

The artificial eyeball registers changes in lighting faster than human eyes can — within about 30 to 40 milliseconds, rather than 40 to 150 milliseconds. The device can also see dim light about as well as the human eye. Although its 100-degree field of view isn’t as broad as the 150 degrees a human eye can take in, it’s better than the 70 degrees visible to ordinary flat imaging sensors.

In theory, this synthetic eye could perceive a much higher resolution than the human eye, because the artificial retina contains about 460 million light sensors per square centimeter. A real retina has about 10 million light-detecting cells per square centimeter. But that would require separate readings from each sensor. In the current setup, each wire plugged into the synthetic retina is about one millimeter thick, so big that it touches many sensors at once. Only 100 such wires fit across the back of the retina, creating images that have 100 pixels.

To show that thinner wires could be connected to the artificial eyeball for higher resolution, Fan’s team used a magnetic field to attach a small array of metal needles, each 20 to 100 micrometers thick, to nanosensors on the synthetic retina one by one. “It’s like a surgical operation,” Fan says.

The researchers’ current method of creating individual ultrasmall pixels is impractical, says Hongrui Jiang, an electrical engineer at the University of Wisconsin–Madison whose commentary on the study appears in the same issue of Nature. “For a few hundred nanowires, okay, fine, but how about millions?” Engineers will need a much more efficient way to manufacture vast arrays of tiny wires on the back of the artificial eyeball to give it superhuman sight, he says.

A new artificial eye mimics and may outperform human eyes


Philip Britz-McKibbin, Professor of Chemistry & Chemical Biology, McMaster University Credit: JD Howell, McMaster University

A team of researchers at McMaster University has developed a reliable and accurate blood test to track individual fat intake, a tool that could guide public health policy on healthy eating.

Establishing reliable guidelines has been a significant challenge for nutritional epidemiologists until now, because they have to rely on study participants faithfully recording their own consumption, creating results that are prone to human error and selective reporting, particularly when in the case of high-fat diets.

For the study, published in the Journal of Lipid Research, chemists developed a test, which detects specific non-esterified fatty acids (NEFAs), a type of circulating free fatty acid that can be measured using a small volume of blood sample.

“Epidemiologists need better ways to reliably assess dietary intake when developing nutritional recommendations,” says Philip Britz-McKibbin, professor in the Department of Chemistry & Chemical Biology at McMaster University and lead author of the study.

“The food we consume is highly complex and difficult to measure when relying on self-reporting or memory recall, particularly in the case of dietary fats. There are thousands of chemicals that we are exposed to in foods, both processed and natural,” he says.

The study was a combination of two research projects Britz-McKibbin conducted with Sonia Anand in the Department of Medicine and Stuart Phillips in the Department of Kinesiology.

Researchers first assessed the habitual diet of pregnant women in their second trimester, an important development stage for the fetus. The women, some of whom were taking omega-3 fish oil supplements, were asked to report on their average consumption of oily fish and full-fat dairy and were then tested with the new technology. Their study also monitored changes in omega-3 NEFAs in women following high-dose omega-3 fish oil supplementation as compared to a placebo.

Researchers were able to prove that certain blood NEFAs closely matched the diets and/or supplements the women had reported, suggesting the dietary biomarkers may serve as an objective tool for assessment of fat intake.

“Fat intake is among the most controversial aspects of nutritional public health policies given previously flawed low-fat diet recommendations, and the growing popularity of low-carb/high-fat ketogenic based diets” says Britz-McKibbin. “If we can measure it reliably, we can begin to study such questions as: Should pregnant women take fish oil? Are women deficient in certain dietary fats? Does a certain diet or supplement lead to better health outcomes for their babies?”

Researchers plan to study what impact NEFAs and other metabolites associated with dietary exposures during pregnancy, might have on childhood health outcomes in relation to the obesity, metabolic syndrome and chronic disease risk later in life.

https://medicalxpress.com/news/2020-05-chemists-foolproof-track-fats.html

By Alice Klein

Hungry bumblebees can coax plants into flowering and making pollen up to a month earlier than usual by punching holes in their leaves.

Bees normally come out of hibernation in early spring to feast on the pollen of newly blooming flowers. However, they sometimes emerge too early and find that plants are still flowerless and devoid of pollen, which means the bees starve.

Fortunately, bumblebees have a trick up their sleeves for when this happens. Consuelo De Moraes at ETH Zurich in Switzerland and her colleagues discovered that worker bumblebees can make plants flower earlier than normal by using their mouthparts to pierce small holes in leaves.

In a series of laboratory and outdoor experiments, the researchers found that bumblebees were more likely to pierce holes in the leaves of tomato plants and black mustard plants when deprived of food. The leaf damage caused the tomato plants to flower 30 days earlier than usual and the black mustard plants to flower 16 days earlier.

It is still a mystery how the leaf damage promotes early blooming. Previous studies have found that plants sometimes speed up their flowering in response to stressors like intense light and drought, but the effects of insect damage haven’t been studied much.

De Moraes and her colleagues were unable to induce early flowering by punching holes in the plant leaves themselves. This suggests that bees may provide additional cues that encourage flowering, like injecting chemicals from their saliva into the leaves when they pierce them. “We hope to explore this in future work,” she says.

Read more: https://www.newscientist.com/article/2244009-bees-force-plants-to-flower-early-by-cutting-holes-in-their-leaves/#ixzz6NBO04hUl


S. Inami et al., “Environmental light is required for maintenance of long-term memory in Drosophila,” J Neurosci, 40:1427–39, 2020.

by Diana Kwon

As Earth rotates around its axis, the organisms that inhabit its surface are exposed to daily cycles of darkness and light. In animals, light has a powerful influence on sleep, hormone release, and metabolism. Work by Takaomi Sakai, a neuroscientist at Tokyo Metropolitan University, and his team suggests that light may also be crucial for forming and maintaining long-term memories.

The puzzle of how memories persist in the brain has long been of interest to Sakai. Researchers had previously demonstrated, in both rodents and flies, that the production of new proteins is necessary for maintaining long-term memories, but Sakai wondered how this process persisted over several days given cells’ molecular turnover. Maybe, he thought, an environmental stimulus, such as the light-dark cycles, periodically triggered protein production to enable memory formation and storage.

Sakai and his colleagues conducted a series of experiments to see how constant darkness would affect the ability of Drosophila melanogaster to form long-term memories. Male flies exposed to light after interacting with an unreceptive female showed reduced courtship behaviors toward new female mates several days later, indicating they had remembered the initial rejection. Flies kept in constant darkness, however, continued their attempts to copulate.

The team then probed the molecular mechanisms of these behaviors and discovered a pathway by which light activates cAMP response element-binding protein (CREB)—a transcription factor previously identified as important for forming long-term memories—within certain neurons found in the mushroom bodies, the memory center in fly brains.

“The fact that light is essential for long-term memory maintenance is fundamentally interesting,” says Seth Tomchick, a neuroscientist at the Scripps Research Institute in Florida who wasn’t involved in the study. However, he adds, “more work will be necessary” to fully characterize the molecular mechanisms underlying these effects.

https://www.the-scientist.com/the-literature/lasting-memories-67441?utm_campaign=TS_DAILY%20NEWSLETTER_2020&utm_source=hs_email&utm_medium=email&utm_content=87927085&_hsenc=p2ANqtz-_7gIn7Nu8ghtWiBtiy6oqTctJuYb31bx6bzhbcV3gVpx0-YoIVNtAhnXXNJT0GC496PAntAiSvYpxLdVAnvITlfOG96g&_hsmi=87927085


Branyas lives in Olot, a city in Catalonia.

By Jack Guy and Al Goodman

A 113-year-old woman, thought to be the oldest in Spain, has said she feels fine after surviving a brush with coronavirus.

Video footage of Maria Branyas, who was born on March 4 1907, shows the super-centenarian speaking to the director of the care home where she lives in Olot, Catalonia.

“In terms of my health I am fine, with the same minor annoyances that anyone can have,” said Branyas in the video. It was recorded Monday, a spokeswoman for the care home told CNN.

Branyas recovered after a mild case of Covid-19. Her battle started shortly after her family visited her on March 4 to celebrate her 113th birthday, the spokeswoman said.

The family has not been able to visit in person since then. Branyas has lived for 18 years in her own private room at the Santa Maria del Tura nursing home, which is run by the Institute of the Order of San Jose of Gerona, affiliated with the Roman Catholic Church, the spokeswoman said.

Branyas was born in San Francisco in the United States, where her father worked as a journalist, reports the AFP news agency.

Over the course of her long life she has survived two world wars as well as the 1918 flu pandemic, which killed more than 50 million people around the world.

Although Branyas recovered from coronavirus, two residents of the same home died of it. The situation at the care home has since improved, said the spokeswoman.

Spain’s state of emergency, in effect since March 14, has strict confinement measures that remain in place. But with the infection and death rates now declining, the government has lifted some lockdown measures in certain parts of the country, on what it says will be a gradual reopening of activity.

But the initial lifting of these restrictions did not apply to Olot, where Branyas lives.

https://www.cnn.com/2020/05/13/europe/spain-oldest-woman-coronavirus-survivor-scli-intl/index.html

by Amy Schleunes

When Lilian Kloft stumbled across a 2015 study showing a connection between cannabis use and susceptibility to false memories, she found herself wondering about the legal implications of the results. The study had discovered that heavy users of cannabis were more likely than controls to form false memories—recollections of events that never occurred, for example, or warped memories of events that did—even when they were not at the moment “high.”

This kind of false remembering can pose difficulties for people gathering reliable testimony in the event of a crime, says Kloft, a PhD student in psychopharmacology and forensic psychology at Maastricht University in the Netherlands. Consequently, the growing acceptance of cannabis worldwide raises questions not only about how the drug affects memory, but also about how law enforcement officials should conduct interviews with suspects, victims, and witnesses who may be under the influence or regular users of the drug.

In order to further investigate the connection between cannabis and false memory formation, Kloft and collaborators recruited 64 volunteers for a series of experiments. Participants, who were occasional cannabis users, were given a vaporizer containing either cannabis or a hemp placebo and then told to inhale deeply and hold their breath for 10 seconds. After that, the researchers tested them in three different tasks designed to induce false memories.

In the first task, the team asked the volunteers to memorize lists of words, and then to pick out those words from test lists that also included dummy words. As expected, both the sober and the intoxicated participants falsely remembered some of the dummy words. But while the sober participants mostly falsely remembered words that were strongly associated with words on the original lists, the intoxicated participants also selected less-related and completely unrelated terms.

In the next two tasks, the researchers wanted to see if they could induce false memories by providing misinformation to the participants. Hoping to imbue these tests with more real-world relevance than a list of words, Kloft and colleagues designed two immersive virtual reality scenarios involving common crimes. In the first, the “eyewitness scenario,” participants observed a fight on a train platform, after which a virtual co-witness recounted the incident but with several errors, including falsely recalling a police dog that wasn’t part of the altercation. In the “perpetrator scenario,” participants entered a crowded bar and were instructed to commit a crime themselves—to steal a purse.

The researchers observed a range of effects associated with cannabis as the intoxicated subjects interacted in these virtual environments. Some participants laughed and talked to the virtual characters in the scenarios, Kloft reports, while others became paranoid and required assistance in stealing the purse. “One person even ran away so quickly that they ripped out the whole VR setup and it fell to the ground,” she says. When researchers interviewed the participants afterward using a combination of leading and non-leading questions, those who were intoxicated showed higher rates of false memory for both the eyewitness and perpetrator scenarios compared with controls.

To look for longer-term effects of cannabis, the experimenters called the subjects back a week later and tested them again on the word lists, this time with a few different dummy words thrown in. They also re-interviewed the subjects about the VR scenarios using a combination of old and new questions. As before, they found lower memory accuracy in the word-association test in those who had been intoxicated compared with sober participants. There were no statistically significant differences between the groups for the virtual reality scenarios, a result that Kloft says may indicate memory decay over time in all participants.

Cognitive neuropsychopharmacologist Manoj Doss, a postdoc at Johns Hopkins University who was not involved in the study, has used word association and other tasks in his own research to demonstrate that tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, increases false memories when participants attempt to retrieve information they’d previously learned. Doss says that the study by Kloft and collaborators is novel not only because it employs virtual reality, but because it shows that both the real-world scenarios and the word association task can induce false memories.

For the tests administered after one week, however, Doss notes that it’s difficult to determine if the researchers were observing actual false memories, because participants might remember both the accurate and the dummy information they encountered in the original experiment. In the follow-up test, “people might say yes to the things they’re not supposed to just because they saw them in that first test,” says Doss. He suggests that increasing the number of items tested, as well as separately analyzing the new and previously used word tests and interview questions, could reveal a higher incidence of false memories in the delayed test for the participants who took cannabis.

Giovanni Marsicano, a neuroscientist at the University of Bordeaux in France who did not participate in the research, says that the new results match up with findings he’s made in mice: animals that receive injections of THC are more likely than controls to associate unrelated stimuli—itself a sort of false memory. His work has also shown that a cannabinoid receptor known as CB1 that is highly abundant in the hippocampus and prefrontal cortex probably plays a key role in the formation of these incidental associations. One of this receptor’s main jobs is to decrease the release of neurotransmitters. Marsicano hypothesizes that when the CB1 receptor is activated, neural signaling is inhibited in such a way that the brain is less able to separate correct from incorrect information.

Roger Pertwee, a pharmacologist at the University of Aberdeen in the UK who was not involved in the research, says that the Dutch team’s results aren’t surprising given what’s known about how cannabinoids affect memory. Unlike endogenous cannabinoids, which tend to selectively activate some CB1 receptors and not others, compounds in cannabis activate all CB1 receptors at once; this indiscriminate activation may also somehow contribute to the formation of false memories, explains Pertwee, who works with GW Pharmaceuticals, a company that makes prescription medicines derived from cannabis.

In the future, Kloft says she’s interested in looking at how people regard the memories they form when high in order to find out whether they “trust” those memories. “Are they confident in them, and is there any strategy they pursue to correct for their probably impaired memory?”

Study coauthor Elizabeth Loftus, a cognitive psychologist and human memory expert at the University of California, Irvine, says that the team’s study should prompt people to think about best practices when it comes to intoxicated witnesses. “The law recognizes that there are vulnerable witnesses who need extra special care and attention when you’re interviewing them: young children, people with mental disabilities, sometimes the elderly are included in that category,” Loftus says. “Might not [people who are high] be another example of . . . vulnerable witnesses where you’ve got to be extra careful?”

https://www.the-scientist.com/notebook/cannabis-increases-propensity-for-false-memories-67473?utm_campaign=TS_DAILY%20NEWSLETTER_2020&utm_source=hs_email&utm_medium=email&utm_content=87631437&_hsenc=p2ANqtz–3qIL8Nng2JbtXCj4SM5wciCtEP1dVQlCZ5bcSGcfOZ4lZ6v_Hyruet-yvSuzp2a67Xy5el2TdFX8Tpyb8oU7OBsMjdg&_hsmi=87631437


A mammoth is depicted on the walls of the Rouffignac caves in France.

By CHRISTIAN COTRONEO

Research published recently in the journal Time and Mind, suggests even our ancient ancestors missed a species they hunted when it disappeared or migrated elsewhere.

That’s because their relationship with animals was much more nuanced than a simple sustenance-based dynamic. Animals were not only hunted, but revered.

“The disappearance of a species that supported human existence for millennia triggered not only technological and social changes but also had profound emotional and psychological effects,” the authors note in the study.

To reach that conclusion, Tel Aviv University researchers looked at hunter-gatherer societies at various points in human history — from as far back as 400,000 years ago to the present — and noted the complex “multidimensional connection” between humans and animals. In all, 10 case studies suggested that bond was existential, physical, spiritual, and emotional

“There has been much discussion of the impact of people on the disappearance of animal species, mostly through hunting,” the study’s lead author Eyal Halfon explains in a press release. “But we flipped the issue to discover how the disappearance of animals — either through extinction or migration — has affected people.”

An animal’s sudden absence, researchers noted, resonates deeply — both emotionally and psychologically — among people who relied on those animals for food. The researchers suspect understanding that impact could help brace us for the dramatic environmental changes happening today.

“We found that humans reacted to the loss of the animal they hunted — a significant partner in deep, varied and fundamental ways,” Halfon notes in the release.

“Many hunter-gatherer populations were based on one type of animal that provided many necessities such as food, clothing, tools and fuel,” he adds. “For example, until 400,000 years ago prehistoric humans in Israel hunted elephants. Up to 40,000 years ago, residents of Northern Siberia hunted the woolly mammoth. When these animals disappeared from those areas, this had major ramifications for humans, who needed to respond and adapt to a new situation. Some had to completely change their way of life to survive.”

A Siberian community, for example, adapted to the disappearance of wooly mammoths by migrating east — and becoming the first known settlers in Alaska and northern Canada. In central Israel, researchers noted, the change from elephants to deer as a hunting source brought physical changes to the humans who lived there. They had to develop agility and social connections, rather than the brute strength required to take down elephants.

But an animal’s disappearance from an environment also created powerful emotional ripples.

“Humans felt deeply connected to the animals they hunted, considering them partners in nature, and appreciating them for the livelihood and sustenance they provided,” Halfon explains. “We believe they never forgot these animals — even long after they disappeared from the landscape.”

Indeed, researchers cite engravings of mammoths and seals from the Late Paleolithic period in Europe as compelling examples of that emotional connection. Both species were likely long gone from that region by the time the engravings were made.

“These depictions reflect a simple human emotion we all know very well: longing,” Halfon notes. “Early humans remembered the animals that disappeared and perpetuated them, just like a poet who writes a song about his beloved who left him.”

Those feelings may even involve a sense of guilt — and maybe even a lesson for a society that lost an animal species.

“Indigenous hunter-gatherer societies have been very careful to maintain clear rules about hunting. As a result, when an animal disappears, they ask: ‘Did we behave properly? Is it angry and punishing us? What can we do to convince it to come back?'” explains study co-author Ran Barkai. “Such a reaction has been exhibited by modern-day hunter-gatherer societies as well.”

https://www.mnn.com/earth-matters/animals/stories/loss-animal-species-human-toll-prehistoric-study?utm_source=Weekly+Newsletter&utm_campaign=7bdab7543a-RSS_EMAIL_CAMPAIGN_WED0506_2020&utm_medium=email&utm_term=0_fcbff2e256-7bdab7543a-40844241