Posts Tagged ‘science’

An unusual new treatment for Tourette’s syndrome involves applying an electrical current to the wrist, which travels up nerves to the brain and changes brainwaves. The approach, which moderately reduced the number of tics in volunteers with Tourette’s, suggests the condition is linked with an underactivity in brainwaves that normally keep us still.

People with Tourette’s syndrome make frequent involuntary jerks, facial twitches and noises. Tics usually arise around the age of 6, and while they often fade with time, for some they continue and can be debilitating. “Sometimes children literally break bones because they’re flinging themselves around so much,” says Stephen Jackson at the University of Nottingham in the UK.

In most people, when they are motionless, brainwaves cycle at about 12 times a second in part of the brain called the motor cortex, located at the top of the head. “It’s like the handbrake on a car – it maintains a stable posture,” says Jackson.

Previous research has shown that stimulating brainwaves in this area by using a strong oscillating magnetic field above the head can reduce tics in people with Tourette’s. Jackson wondered if there was a way to get this effect more easily.

His group placed an electrode on the wrist to deliver a mild current with a frequency of 12 times a second; the current was noticeable but not uncomfortable. The idea is that this current travels via nerves to the sensory cortex of the brain and induces oscillations at the same frequency in the neighbouring motor cortex.

When 19 people with Tourette’s tried out the electrode, it reduced the frequency of their tics by a third, compared with when the electrode was turned on for the same length of time but had no regular frequency. Voluntary movements were only slowed a little.

Normally people with Tourette’s feel an urge to tic slowly building until it becomes irresistable. Many of the volunteers reported that when the electrodes were at the right frequency, their urges reduced. Charlie, a 21-year-old with severe tics, said in a statement: “When the electrical pulses on the wrist started to increase, the tic urges decreased, which was a completely shocking experience for me, I was silent and still. I wanted to cry with happiness.”

Jackson’s group is developing a watch-like device that people can turn on to deliver the stimulation when it is needed.

Journal reference: Current Biology, DOI: 10.1016/j.cub.2020.04.044

Read more: https://www.newscientist.com/article/2245275-electric-current-helps-dampen-tics-in-people-with-tourettes-syndrome/#ixzz6OUvidHok


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


Human cell types within corresponding organs that express the genes for both ACE2 and CTSL (green dot) or both ACE2 and TMPRSS2 (orange dot).

by Chris Baraniuk

When the SARS-CoV-2 virus enters the human body, it breaks into cells with the help of two proteins that it finds there, ACE2 and TMPRSS2. While there has been much discussion of viral infection in gut and lung cells, researchers have dug into massive gene expression datasets to show that other potential target cells also producing ACE2 and TMPRSS2 are scattered throughout the body—including in the heart, bladder, pancreas, kidney, and nose. There are even some in the eye and brain.

The results, published in a preprint on bioRxiv April 21, show that such cells are strikingly abundant. Many are epithelial cells, which line the outer surface of organs. The new findings add to an emerging picture of SARS-CoV-2 as a virus that can target cells in many places in the human body, rather than being focused on a particular organ or part of the respiratory tract.

Cardiologist Frank Ruschitzka at the University Hospital of Zürich and colleagues separately published a letter in The Lancet April 17 in which they described how virus particles had been found in the vascular endothelium, a thin layer of cells lining blood vessels in various organs of the body, for instance.

“This is not just a virus pneumonia,” Ruschitzka, who was not involved in the latest study, tells The Scientist, referring to COVID-19. “This is a disease like we have never seen before—it is not an influenza, it hits the vessels all over, it hits the heart as well.”

To uncover the locations of cells bearing ACE2 and TMPRSS2, the preprint researchers turned to the Human Cell Atlas, a project that has allowed scientists to pool together data on human cells since 2016.

By scouring single-cell sequencing records of around 1.2 million individual cells from human tissue samples, the team was able to find out which of those cells produce both ACE2 and TMPRSS2, and note their locations in the body. The analysis used 16 unpublished datasets of lung and airway cells and 91 published datasets spanning a range of human organs.

Coauthor Christoph Muus, a graduate student at Harvard University and the Broad Institute, explains that while the data show cells in many locations in the body produce SARS-CoV-2 receptors, it’s not certain that the virus can infect all of those tissues.

“Expressing the receptor is a necessary condition but not necessarily a sufficient condition,” he says. For example, potential target cells were found in the testes, but scientists still don’t know if SARS-CoV-2 infects and replicates in that part of the body.

Jeremy Kamil, a virologist at Louisiana State University Health Shreveport, says the preprint provides important details about the human body that may help scientists understand how SARS-CoV-2 infects hosts. By finding viral protein fragments in tissue samples from patients who died because of COVID-19, scientists might be able to firm up which organs are genuine sites of infection, he adds.

“I’d say this paper gives people a roadmap at where you might want to look in the body to understand where this virus is going,” he says.

One limitation of the work is that relatively little metadata about the people who donated tissue samples were available for the various datasets, though information about age and gender were included in many. The researchers don’t know, for example, whether there was an ethnicity bias in the data, whether patients had pre-existing conditions, or whether they were taking any medications. All of these things could affect gene expression in particular cells.

Smoking status was available for a subset of the data, and the team used this to show that smoking is correlated with a greater expression of the ACE2 gene in the upper airway, but lower expression in certain lung cells. Further research is needed to understand whether this affects smokers’ susceptibility to COVID-19. Data from China suggest that smokers are 14 times more likely to develop a severe form of the disease.

Some researchers from the same group using similar data have also recently published papers in Cell and Nature. In those cases, the researchers focused on certain groups of cells. The study reported in Nature examined cells potentially involved in viral transmission and found that nasal epithelial cells, in particular, were associated with expression of ACE2 and TMPRSS2. The authors report that the virus might exploit cells that secrete fluids in the nasal passage, which might help it spread from one person to another in droplets released, say, when someone sneezes.

The Cell study, meanwhile, also found ACE2 and TMPRSS2 transcripts in nasal, gut, and lung cells but the researchers also found that the protein interferon activated ACE2 expression in vitro. The human body uses interferon to fight infections, so it is not clear whether the protein is of overall benefit or detriment to COVID-19 patients.

The use of so many different data sources backs up the validity of the preprint authors’ findings, says Marta Gaglia, a molecular biologist at Tufts University. She agrees with the researchers that discovering ACE2- and TMPRSS2-producing cells in various places around the body does not prove the virus can always infect such cells.

“I think the reality is that most of the problems come from the lung,” she adds. Plus, while doctors treating COVID-19 patients may detect problems in multiple organs, those issues might not necessarily be caused directly by SARS-CoV-2 infection, says Gaglia. A problematic immune system response, for instance, could damage certain tissues in the body as an indirect consequence of viral infection.

https://www.the-scientist.com/news-opinion/receptors-for-sars-cov-2-present-in-wide-variety-of-human-cells-67496?utm_campaign=TS_DAILY%20NEWSLETTER_2020&utm_source=hs_email&utm_medium=email&utm_content=87213170&_hsenc=p2ANqtz-_vGzY0JSZbqON-CbrWnU2wp22vNPAa-zcPDPoSZR69MA0qXhi3ukYIXekJJKZ_A_GfMi8lV1cuO5y2DnnkhV-rdYFrPQ&_hsmi=87213170


June Almeida with her electron microscope at the Ontario Cancer Institute in Toronto in 1963

The woman who discovered the first human coronavirus was the daughter of a Scottish bus driver, who left school at 16.

June Almeida went on to become a pioneer of virus imaging, whose work has come roaring back into focus during the present pandemic.

Covid-19 is a new illness but it is caused by a coronavirus of the type first identified by Dr Almeida in 1964 at her laboratory in St Thomas’s Hospital in London.

The virologist was born June Hart in 1930 and grew up in a tenement near Alexandra Park in the north east of Glasgow.

She left school with little formal education but got a job as a laboratory technician in histopathology at Glasgow Royal Infirmary.

Later she moved to London to further her career and in 1954 married Enriques Almeida, a Venezuelan artist.

Common cold research
The couple and their young daughter moved to Toronto in Canada and, according to medical writer George Winter, it was at the Ontario Cancer Institute that Dr Almeida developed her outstanding skills with an electron microscope.

She pioneered a method which better visualised viruses by using antibodies to aggregate them.

Mr Winter told Drivetime on BBC Radio Scotland her talents were recognised in the UK and she was lured back in 1964 to work at St Thomas’s Hospital Medical School in London, the same hospital that treated Prime Minister Boris Johnson when he was suffering from the Covid-19 virus.

On her return, she began to collaborate with Dr David Tyrrell, who was running research at the common cold unit in Salisbury in Wiltshire.

Mr Winter says Dr Tyrrell had been studying nasal washings from volunteers and his team had found that they were able to grow quite a few common cold-associated viruses but not all of them.

One sample in particular, which became known as B814, was from the nasal washings of a pupil at a boarding school in Surrey in 1960.

They found that they were able to transmit common cold symptoms to volunteers but they were unable to grow it in routine cell culture.

However, volunteer studies demonstrated its growth in organ cultures and Dr Tyrrell wondered if it could be seen by an electron microscope.

They sent samples to June Almeida who saw the virus particles in the specimens, which she described as like influenza viruses but not exactly the same.

She identified what became known as the first human coronavirus.


Coronaviruses are a group of viruses that have a halo or crown-like (corona) appearance when viewed under a microscope.

Mr Winter says that Dr Almeida had actually seen particles like this before while investigating mouse hepatitis and infectious bronchitis of chickens.

However, he says her paper to a peer-reviewed journal was rejected “because the referees said the images she produced were just bad pictures of influenza virus particles”.

The new discovery from strain B814 was written up in the British Medical Journal in 1965 and the first photographs of what she had seen were published in the Journal of General Virology two years later.

According to Mr Winter, it was Dr Tyrrell and Dr Almeida, along with Prof Tony Waterson, the man in charge at St Thomas’s, who named it coronavirus because of the crown or halo surrounding it on the viral image.

Dr Almeida later worked at the Postgraduate Medical School in London, where she was awarded a doctorate.

She finished her career at the Wellcome Institute, where she was named on several patents in the field of imaging viruses.

After leaving Wellcome, Dr Almeida become a yoga teacher but went back into virology in an advisory role in the late 1980s when she helped take novel pictures of the HIV virus.

June Almeida died in 2007, at the age of 77.

Now 13 years after her death she is finally getting recognition she deserves as a pioneer whose work speeded up understanding of the virus that is currently spreading throughout the world.

https://www.bbc.com/news/uk-scotland-52278716

By Olivia Konotey-Ahulu

A vaccine against the coronavirus could be ready by September, according to a scientist leading one of Britain’s most advanced teams.

Sarah Gilbert, professor of vaccinology at Oxford University, told The Times on Saturday that she is “80% confident” the vaccine would work, and could be ready by September. Experts have warned the public that vaccines typically take years to develop, and one for the coronavirus could take between 12 to 18 months at best.

In the case of the Oxford team, however, “it’s not just a hunch, and as every week goes by we have more data to look at,” Gilbert told the London newspaper.

Gilbert’s team is one of dozens worldwide working on a vaccine and is the most advanced in Britain, she told the Times. As the country looks set to begin its fourth week under lockdown, a vaccine could be fundamental in easing the measures and returning to normal life. Gilbert said human trials are due to start in the next two weeks.

Her remarks came as the death toll from the virus pushed past 100,000 globally. On Friday, the U.K. reported 980 fatalities, taking the total count from the virus to 8,958, and the government has repeatedly pleaded with the public to obey lockdown rules during the long Easter holiday weekend. As Prime Minister Boris Johnson begins his recovery after a spell in intensive care, Patrick Vallance, the government’s chief scientific adviser, warned he expects the number of deaths to increase for “a few weeks” yet.

Manufacturing the millions of vaccine doses necessary could take months. Gilbert said she’s in discussions with the British government about funding, and starting production before the final results are in, allowing the public to access the vaccine immediately if it proves to work. She said success by the autumn was “just about possible if everything goes perfectly.”

https://www.bloomberg.com/news/articles/2020-04-11/coronavirus-vaccine-could-be-ready-in-six-months-times


The company behind the breakthough, Carbios, has partnered with major companies including Pepsi and L’Oréal. Photograph: Mario Anzuoni/Reuters

A mutant bacterial enzyme that breaks down plastic bottles for recycling in hours has been created by scientists.

The enzyme, originally discovered in a compost heap of leaves, reduced the bottles to chemical building blocks that were then used to make high-quality new bottles. Existing recycling technologies usually produce plastic only good enough for clothing and carpets.

The company behind the breakthrough, Carbios, said it was aiming for industrial-scale recycling within five years. It has partnered with major companies including Pepsi and L’Oréal to accelerate development. Independent experts called the new enzyme a major advance.

Billions of tonnes of plastic waste have polluted the planet, from the Arctic to the deepest ocean trench, and pose a particular risk to sea life. Campaigners say reducing the use of plastic is key, but the company said the strong, lightweight material was very useful and that true recycling was part of the solution.

The new enzyme was revealed in research published on Wednesday in the journal Nature. The work began with the screening of 100,000 micro-organisms for promising candidates, including the leaf compost bug, which was first discovered in 2012.

“It had been completely forgotten, but it turned out to be the best,” said Prof Alain Marty at the Université de Toulouse, France, the chief science officer at Carbios.

The scientists analysed the enzyme and introduced mutations to improve its ability to break down the PET plastic from which drinks bottles are made. They also made it stable at 72C, close to the perfect temperature for fast degradation.

The team used the optimised enzyme to break down a tonne of waste plastic bottles, which were 90% degraded within 10 hours. The scientists then used the material to create new food-grade plastic bottles.

Carbios has a deal with the biotechnology company Novozymes to produce the new enzyme at scale using fungi. It said the cost of the enzyme was just 4% of the cost of virgin plastic made from oil.

Waste bottles also have to be ground up and heated before the enzyme is added, so the recycled PET will be more expensive than virgin plastic. But Martin Stephan, the deputy chief executive at Carbios, said existing lower-quality recycled plastic sells at a premium due to a shortage of supply.

“We are the first company to bring this technology on the market,” said Stephan. “Our goal is to be up and running by 2024, 2025, at large industrial scale.”

He said a reduction in plastic use was one part of solving the waste problem. “But we all know that plastic brings a lot of value to society, in food, medical care, transportation. The problem is plastic waste.” Increasing the collection of plastic waste was key, Stephan said, with about half of all plastic ending up in the environment or in landfill.

Another team of scientists revealed in 2018 that they had accidentally created an enzyme that breaks down plastic drinks bottles. One of the team behind this advance, Prof John McGeehan, the director of the Centre for Enzyme Innovation at the University of Portsmouth, said Carbios was the leading company engineering enzymes to break down PET at large scale and that the new work was a major advance.

“It makes the possibility of true industrial-scale biological recycling of PET a possibility. This is a very large advance in terms of speed, efficiency and heat tolerance,” McGeehan said. “It represents a significant step forward for true circular recycling of PET and has the potential to reduce our reliance on oil, cut carbon emissions and energy use, and incentivise the collection and recycling of waste plastic.”

Scientists are also making progress in finding biological ways to break down other major types of plastic. In March, German researchers revealed a bug that feasts on toxic polyurethane, while earlier work has shown that wax moth larvae – usually bred as fish bait – can eat up polythene bags.

https://www.theguardian.com/environment/2020/apr/08/scientists-create-mutant-enzyme-that-recycles-plastic-bottles-in-hours?CMP=oth_b-aplnews_d-1