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How children are spoofing Covid-19 tests with soft drinks – BBC News

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Some children have found a devious method to get out of school – using cola to create false positive Covid tests. How does it work?

Children are always going to find cunning ways to bunk off school, and the latest trick is to fake a positive Covid-19 lateral flow test (LFT) using soft drinks. [Videos of the trick have been circulating on TikTok since December and a school in Liverpool, UK, recently wrote to parents to warn them about it.] So how are fruit juices, cola and devious kids fooling the tests, and is there a way to tell a fake positive result from a real one? I’ve tried to find out.

First, I thought it best to check the claims, so I cracked open bottles of cola and orange juice, then deposited a few drops directly onto LFTs. Sure enough, a few minutes later, two lines appeared on each test, supposedly indicating the presence of the virus that causes Covid-19.

It’s worth understanding how the tests work. If you open up an LFT device, you’ll find a strip of paper-like material, called nitrocellulose, and a small red pad, hidden under the plastic casing below the T-line. Absorbed on the red pad are antibodies that bind to the Covid-19 virus. They are also attached to gold nanoparticles (tiny particles of gold actually appear red), which allow us to see where the antibodies are on the device. When you do a test, you mix your sample with a liquid buffer solution, ensuring the sample stays at an optimum pH, before dripping it on the strip.

The fluid wicks up the nitrocellulose strip and picks up the gold and antibodies. The latter also bind to the virus, if present. Further up the strip, next to the T (for test), are more antibodies that bind the virus. But these antibodies are not free to move – they are stuck to the nitrocellulose. As the red smear of gold-labelled antibodies pass this second set of antibodies, these also grab hold of the virus. The virus is then bound to both sets of antibodies – leaving everything, including the gold, immobilised on a line next to the T on the device, indicating a positive test.

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Gold antibodies that haven’t bound to the virus carry on up the strip where they meet a third set of antibodies, not designed to pick up Covid-19, stuck at the C (for control) line. These trap the remaining gold particles, without having to do so via the virus. This final line is used to indicate the test has worked.

The acidity of many soft drinks and fruit juices can lead to false positives in the Covid-19 lateral flow test but still be negative with a PCR test (Credit: Mark Lorch)

So, how can a soft drink cause the appearance of a red T line? One possibility is that the drinks contain something that the antibodies recognise and bind to, just as they do to the virus. But this is rather unlikely. The reason antibodies are used in tests like these is that they are incredibly fussy about what they bind to. There’s all sorts of stuff in the snot and saliva collected by the swabs you take from the nose and mouth, and the antibodies totally ignore this mess of protein, other viruses and remains of your breakfast. So they aren’t going to react to the ingredients of a soft drink.

A much more likely explanation is that something in the drinks is affecting the function of the antibodies. A range of fluids, from fruit juice to cola, have been used to fool the tests, but they all have one thing in common – they are highly acidic. The citric acid in orange juice, phosphoric acid in cola and malic acid in apple juice give these beverages a pH between 2.5 and 4. These are pretty harsh conditions for antibodies, which have evolved to work largely within the bloodstream, with its almost neutral pH of about 7.4.

Maintaining an ideal pH for the antibodies is key to the correct function of the test, and that’s the job of the liquid buffer solution that you mix your sample with, provided with the test. The critical role of the buffer is highlighted by the fact that if you mix cola with the buffer – as shown in this debunking of an Australian politician’s claim that mass testing is worthless – then the LFTs behave exactly as you’d expect: negative for Covid-19.

So without the buffer, the antibodies in the test are fully exposed to the acidic pH of the beverages. And this has a dramatic effect on their structure and function. Antibodies are proteins, which are comprised of amino acid building blocks, attached together to form long, linear chains. These chains fold up into very specific structures. Even a small change to the chains can dramatically impact a protein’s function. These structures are maintained by a network of many thousands of interactions between the various parts of the protein. For example, negatively charged parts of a protein will be attracted to positively charged areas.

Many schools in the UK have used regular lateral flow testing to check whether pupils might be carrying the Covid-19 virus (Credit: Oli Scarff/AFP/Getty Images)

Many schools in the UK have used regular lateral flow testing to check whether pupils might be carrying the Covid-19 virus (Credit: Oli Scarff/AFP/Getty Images)

But in acidic conditions, the protein becomes increasingly positively charged. As a result, many of the interactions that hold the protein together are disrupted, the delicate structure of the protein is affected and it no longer functions correctly. In this case, the antibodies’ sensitivity to the virus is lost.

Given this, you might expect that the acidic drinks would result in completely blank tests. But denatured proteins are sticky beasts. All of those perfectly evolved interactions that would normally hold the protein together are now orphaned and looking for something to bind to. A likely explanation is that the immobilised antibodies at the T-line stick directly to the gold particles as they pass by, producing the notorious cola-induced false positive result.

Is there then a way to spot a fake positive test? The antibodies (like most proteins) are capable of refolding and regaining their function when they are returned to more favourable conditions. So I tried washing a test that had been dripped with cola with buffer solution, and sure enough the immobilised antibodies at the T-line regained normal function and released the gold particles, revealing the true negative result on the test.

Children, I applaud your ingenuity, but now that I’ve found a way to uncover your trickery I suggest you use your cunning to devise a set of experiments and test my hypothesis. Then we can publish your results in a peer-reviewed journal.

* Mark Lorch is a professor of chemistry and science communication at the University of Hull, UK.

This article originally appeared on The Conversation, and is republished under a Creative Commons licence. 

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To help chart the cosmos, Western space researchers turn to crowd sourcing – CBC.ca

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Western University researchers have tapped the help of hundreds of amateur and professional astronomers in an effort to make sure no meteor is unable to slip by the Earth undetected.

To do that, they’re relying on the observations taken from 450 cameras in 30 different countries manned by “enthusiastic amateur astronomers” made up of professional and citizen scientists.

That data is then sent to Western University as part of what’s called the Global Meteor Network (GMN), headed by Denis Vida.

“So we have a lot of enthusiastic amateur astronomers, citizen scientists and also professionals that build, operate and maintain these cameras,” Vida told CBC’s Chris dela Torre during Afternoon Drive. “And every night they inspect the data set and send their data to a central server here at the University of Western Ontario.”

It’s not just about observing meteors – it’s about tracking what’s left of the ones that make it to the earth’s surface too.

“So we also observe a meteorite dropping fireballs,” said Vida. “They’re quite rare over an area of let’s say the country the size of France or Spain. Could only expect two to three of those fireballs a year that drop more than, let’s say, 300 grams of meteorites on the ground.”

“So because these events are very rare, it is important to observe 24/7.”

Vida explained that when one of their cameras spot one of them, they collect the data and find its location so they can retrieve what’s left for analysis – and analysis needs to happen quickly.  

“There are certain things in them, like some radionuclide to decay very quickly, but those can tell us how old the meteorite is, how long it was after it was ejected from the parent asteroid that it fell on the ground,” he said.

Vida explained that what ends up on the ground are just “several kilograms of materials” by the time they reach the earth’s surface. They aren’t hot either. They cool down on their descent.

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Global push to monitor meteor showers led by Western University – CTV News London

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MIDDLESEX CENTRE, ONT. —
London, Ont.’s Western University is leading a worldwide effort to monitor meteor showers and meteorite falls.

The Global Meteor Network (GMN) includes more than 450 cameras in 23 countries – hosted by amateur and professional astronomers.

The goal of the project, led by Denis Vida, a postdoctoral associate at Western, is to ensure unique or rare space events are not missed.

Vida explained in a statement, “Other astronomers can pool their resources to build a big telescope on top of a mountain where the skies are dark and clear year-round, but meteor astronomers need spatial coverage most of all.”

Meteors can occur anywhere in the world, happen close to earth and often burn up at around 100 km above the surface — so they can only be well observed from within about 300 km and need to be seen by cameras in at least two places to get the exact location.

That’s where the Global Meteor Network comes in.

In March, the network helped locate a rare portion of a meteorite that landed in Winchcombe, England on Feb. 28 and figure out where in space it originated.

“Its role in the recovery and analysis of the Winchcombe meteorite fall is proof positive that GMN works,” said Vida.

The first system to observe meteorites was installed at Western in 2017, and it continues to grow as the cost of meteor cameras has declined.

GMN also publishes the orbits of all observed meteors around the world within 24 hours of observation. The location of cameras and meteor data can be seen here.

The network also hopes to better understand flight patterns and flux capacities of meteorites, and even predict future events.

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MDA gets $35.3 million contract from Canadian Space Agency for Canadarm 3 components – Times Colonist

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BRAMPTON, Ont. — The Canadian Space Agency has awarded a contract worth $35.3 million to MDA Ltd. to design a key component of Canadarm 3.

The funds will be used to design Gateway External Robotics Interfaces or grapple fixtures for Canadarm 3, which is Canada’s contribution to the United States-led Lunar Gateway, a small space station that will orbit the moon.

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The contract is a follow-on to the first phase of interface work awarded in August 2019. A construction phase will likely be awarded in about a year.

The first elements of Gateway will launch in 2024, with Canadarm 3 scheduled to launch two years later.

The contract is the third awarded to MDA for the multi-phase Canadarm 3 program valued at more than $1 billion.

Canadarm flew on 90 space shuttle missions after debuting in 1981. Canadarm 2 has been operating on the International Space Station for more than 20 years.

This report by The Canadian Press was first published July 26, 2021.

Companies in this story: (TSX:MDA)

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