science news

Great Explanations – Crowdfunded science anthology

Excuse the slight off (chemistry) topic post, but I wanted to let folks know about a crowdfunded science anthology I’ve launched via Unbound.

You don’t need a PhD in horology to know that there are piles of great popular science books out there and not enough time to read them all. So I’ve collected a bunch of the best established and emerging science writers – people working at the cutting edge of their own particular disciplines – and asked them to distil their passions into just one chapter each.

The result is Great Explanations, an anthology of the most pressing, fascinating and sometimes just plain overlooked topics from the far reaches of science, engineering and maths topped with a smattering of the philosophy and history of science. These are the subjects that working scientists are most passionate about, or interested in, or surprised by, in their own disciplines – the things they think curious general readers really ought to know.

We’ve also teamed up with Sense about Science, which promotes the public interest in sound science and evidence. Some of the contributing authors are part of their Voice of Young Science network and 15% of the book’s profits will be donated to the charity.

Contributors include:

A whole load more fabulous scientists and writers will be revealed over the next few weeks; stay tuned to our updates to be among the first to find out more.

Of course, if it doesn’t get funded the book will never exist, so pop over to Unbound and pledge!

https://unbound.com/books/great-explanations/

By September 5, 2021 0 comments science events, science news

COVID-19 tests encased on coffee machine capsules

Transitioning to home working had its challenges for us all, but when your job involves researching biological applications for nanotechnology, those trials are a little more complicated than juggling the household’s broadband usage. So barred from his lab, you might reasonably expect the research by organic chemist Vittorio Saggiomo, from the Bionanotechnology group at Wageningen University & Research in the Netherlands, to have come to a grinding halt.

But Saggiomo is a creative, imaginative type, and so he began to wonder if he could turn common household appliances to good use in the fight against COVID-19. More specifically, could he create a cheap, highly sensitive home test for the virus? It turns out he could. His team has now posted the idea on a preprint server, ChemArxiv. The paper is yet to be reviewed by other scientists.

At the moment, there are two main types of COVID-19 test: the PCR test and the lateral flow test (LFT). The gold-standard PCR test checks for the presence of the virus by detecting its genetic material known as RNA. But there are vanishingly small amounts of viral material in a swab, so the material has to be converted into DNA and amplified before it can be detected. And this is achieved by the “polymerase chain reaction”, which is what PCR stands for.

The process involves repeated cycling through a range of temperatures between 50°C and 90°C. During each cycle, the amount of DNA doubles, so after 30 cycles over a billion copies of the viral material can be created from just one strand of starting material. The amplified material is then detected with fluorescent labels that attach themselves to the viral DNA sequences.

As such, PCR is a highly sensitive technique, but it needs specialist materials and equipment to perform. This is why the tests are sent off to a lab, and it takes a day or two to get the result.

The second common test is the lateral flow test (LFT). These work by detecting fragments of viral protein shells. Embedded within the strips of the LFTs are antibodies that bind to the virus. These antibodies are labelled with tiny gold particles, which appear red, allowing you to see them on the test device. The labelled antibodies accumulate on distinct bands on the LFT depending on whether the virus is present or not.

The LFTs are fast, cheap and easy to use, making them ideal for community and home testing. But they are nowhere near as sensitive as the PCR tests – they will only identify people with high viral loads. This means many people who are infected will get a false negative result from such tests.

CoroNaspresso tests

Ideally, we need a home test that’s as easy to use as the LFTs but as sensitive as the PCR test. An excellent candidate is a method called loop-mediated isothermal amplification (Lamp). This works along very similar principles to PCR, producing multiple copies of the starting genetic material – which you can get from a swab – but has some key advantages.

For example, it can be combined with a handy “colour readout”. When the Lamp reaction occurs, it causes an increase in the acidity of the sample. That means you can add a substance that changes colour according to pH value in the reaction mix, providing a visual indication of a positive or negative result. Another advantage is that Lamp reactions are carried out at a fixed temperature (about 65°C) instead of needing constant cycling through a range of temperatures.

Nevertheless, Lamp still needs fine temperature control. Temperature control systems – be they in a PCR machine, a Lamp instrument or household oven – are usually achieved with electronic thermostats. However, making and shipping new electronic devices specifically designed for home Lamp tests is impractical (especially in the middle of a pandemic). So Saggiomo tried to find a way around this. He hit upon substances called phase change materials that absorb energy (heat) as they melt and so maintain a constant temperature.

After finding a wax made of such a material that melted at exactly the required temperature, Saggiomo set about constructing a device to house the Lamp reaction tubes and chunks of wax. This then needed to be inserted into some other material that could be heated. The perfect housing turned out to be staring him in the face while making his morning coffee: Nespresso coffee machine capsules.

The final step was just finding the right way to heat the capsules. After trying the dishwasher (it worked but samples kept getting lost), the microwave oven (failed, because the tubes overheated and lids popped off) and cups full of hot water (not enough control on the temperature), Saggiomo settled on a simple pan of simmering water on a stovetop. The resulting “CoroNaspresso” device, when tested by other members of the team, with swabs from six people, correctly identified three cases of COVID-19 (these had a different colour to the negative tests).

Home covid test.
Tweet by @V_Saggiomo

The test, including the capsules, phase changing wax and vials in which to insert genetic material, would be easy to produce in millions. People could then swab for genetic material at home and heat the capsules to get their results. These devices are also cheap (about €0.20), easy to make, easy to use and largely recyclable. Maybe we’ll see the CoroNespresso tests in our homes soon, just don’t get them confused with your regular coffee pods.The Conversation

Mark Lorch, Professor of Science Communication and Chemistry, University of Hull

This article is republished from The Conversation under a Creative Commons license. Read the original article.

By April 9, 2021 9 comments lab technique, science news

What links self-heating drinks and the D-day landings?


The imposing cliffs of Pointe de Hoc overlook the Normandy beaches where Allied troops landed on June 6 1944. The assaults marked the beginning of the liberation of German-occupied Europe. And the cliff tops were the perfect spot for artillery pieces capable of devastating any troops who tried to attack the Omaha and Utah beachheads.

The Allied command knew this and so, to shore up the attack, the navy bombarded Pointe de Hoc. Afraid this might not be enough, they also had a backup plan. A team of US Rangers scaled the 30-metre cliffs and, after locating the weaponry, deployed grenades, destroying the guns. The key to success was the choice of thermite-based charges. Yup, just good old iron oxide and aluminium.

 

 

Ok, so what this got to do with self-heating cans?

Link number 1:  Some of the same troops who were landing on the Normandy beaches that day had self-heating soap cans.

These were essentially a stove and can rolled into one, with a tube of cordite (more typically used as the propellant in small arms ammunition) running through the centre of the can to act as fuel. The cans were quick and easy to use and could be lit with a cigarette, allowing troops to prepare a hot meal in under five minutes. Unfortunately, they also had a tendency to explode, showering the assembled squaddies with piping hot soup.

Self-heating cocoa. University of Cambridge

Since then, there have been numerous attempts to make self-heating cans into a mainstream product. Most relied on a rather less volatile reaction to provide the heat, although some have still struggled with explosive issues.  Calcium oxide heats up rapidly when mixed with water. But it’s not particularly efficient, producing about 60 calories of energy per gram of reactant.

The upshot is that, to heat the drink by 40℃, you need a heating element that takes up nearly half the packaging. That’s just about OK if you want a small drink on a warm day, but in the depths of winter, when you might really want a hot drink, you only end up with a tepid coffee.

More powerful cans

What’s needed is a much more efficient reaction. Something, like thermite perhaps? As crazy as packing a can with a reaction capable of disabling an artillery gun may seem, that’s just what HeatGenie is planning. Over the last ten years, the firm has filed numerous patents describing the use of thermite within self-heating cans. It turns out the reaction used by the US Rangers is still too hot to handle, so they’ve dialled things back a bit by replacing the rust with a less reactive but no less familiar material, silicon dioxide. So the latest generation of heated cans is fuelled on aluminium and ground-up glass.

When this reaction is triggered it still kicks out a whopping 200 calories per gram of reactant and can achieve 1,600℃. Given the troubled history of self-heating packaging, releasing this much energy from the can in your hand might be a bit of a concern, so several of HeatGenie’s patents cover safety issues.

These include a complex arrangement of “firewalls” that can block the so-called “flamefront” should things get too hot, and energy-absorbing “heatsinks” to ensure the heat is efficiently transmitted around the drink, as well as vents to let off any steam. With all that is place, the company claims just 10% of the packaging is taken up by the heating elements, which can still produce a warm coffee in two minutes (although the exact temperature hasn’t been revealed).

A US technology firm is hoping to make a very old idea finally work by launching self-heating drinks cans. HeatGenie recently received US$6m to bring its can design to market in 2018, . Yet the principles behind the technology go back much further – to 1897, when invented the first self-heating can. So how do these cans work, why has no one has managed to make them a success, and what’s HeatGenie’s new approach? To answer that, we have to go back to World War II.

The ConversationSo, well over a century on fromRussian engineer Yevgeny Fedorov first attempts to make self-heating cans and more than 15 years after Nestle abandoned a similar idea, has HeatGenie final cracked it? Judging from the patents and investments, the firm might have sorted out the technical side, but whether it really has a hot product on its hands is another thing entirely.

This article was originally published on The Conversation. Read the original article.

By June 22, 2018 19 comments general chemistry, science news

2050 – A world without plastics


An experimental bit of writing – be nice 😉

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The 20th centuries wonder material had turned into a blight of biblical proportions. The world was awash with plastic. From obvious fragments of polystyrene packaging, to polyethene shopping bags, and discarded PVC furniture to the microscopic micro-fibres shed from our polyester clothing during every wash. It accumulated in great, becalmed garbage patches in the middle of our oceans or washed up as vast invasions of flotsam, where it was consumed by wildlife, mistaking our discarded packaging for food.

Meanwhile the currents and geological forces abraded the jet-sum into tiny fragments that found their way into, well everything. Our cheap, durable and omni-present material had reached every corner of the globe, it had became part of the very fabric of the planet. Geologists coined a new type of sedimentary rock; plastiglomerate – part plastic pollution part stone.

For decades the litter had been building. The obvious detritus featured on every street corner, beach and country park. It became part of the scenery, we got used to it, ignored it, or mildly complained, whilst making sure we kept hydrated by sipping from our water bottles, that we clutched like life-support systems.

Then almost two decades into the 21st century the zeitgeist shifted. Seemingly triggered by the haunting image of pilot whale grieving her dead cub. The narrator blamed plastics. Our blinkers fell away, and we noticed the plastic as if it had just been dumped on our doorsteps. Unlike the invisible carbon dioxide, ravishing the climate and the oceans, we could point at this culprit.

Almost overnight plastic packaging became universally distasteful. Shoppers curled their lips when offered a plastic punnet of mushrooms and then stripped of the useless artificial skins from their purchases before dumping them in front of the supermarkets. Companies raced to see who could strip the plastic from their products the quickest. Listicle blogs sprang up providing tips on how to throw the ultimate plastic free dinner party. And, much to children’s dismay, drinking straws disappeared from cafes across the land.

Politicians were as quick to jump on the bandwagon, keen to cash in on the voters’ new plastic outrage, they vilified cotton buds, toothpicks and wet wipes.

But all this outrage, bans and boycotts was just tinkering around the edges. One small island’s war on drinking straws did little more than remove a mole hill from the mountain of the world’s plastic waste. Something much more radical was needed.

Gaia had the beginnings of an answer. She was used to cleaning up detritus. Over millions of years the myriad of micro-fauna have found biochemical ways to harness the resources from organic dead matter. But plastics had only been around for a few decades. So microorganisms simply hadn’t had enough time to evolve the necessary biochemical tool kit to latch onto the plastic fibres, break them up and then utilise the resulting chemicals as a source of energy and carbon that they need to grow.

Or so we thought.

But deep within a Japanese rubbish tip, devoid of organic matter on which to feed, evolutionary pressure had selected an organism with a new feeding strategy. Nature it seemed, had quietly made a start on tackling our plastic plague. Somewhen, in the recent past, a bacteria had undergone a random mutation and a protein that normally allowed the bug to feed on fats had been converted into one that empowered it to digest plastics.

Not that the plastic waste was noticeably decomposing. The bacteria wasn’t up to the scale of the job. After all, it was a mere evolutionary infants, taking the first tentative bites of a new food, still unequipped to make full use of it. It might have been decades or longer before anyone noticed the rubbish was rotting. Or maybe some other natural pressure may have been to much for the new species. It could so easily have gone extinct before anyone ever became aware of its existence.

But for Prof Yoshiharu Kimura’s eureka moment. Struck by an inspiration particle, it occurred to him that the obvious place to look for a plastic eating organism was in the heaps of rubbish. For five years he hunted through 100s of samples of soil, sludge and stagnant water seeping out of tips and recycling plants. Then, back in the lab, he painstakingly tried to grow something, anything, by feeding his soup of organisms little more than ground up polythene bottles. Miraculously, in just one dish a single bacteria flourished, multiplied and thrived. Soon he had a viable culture. Professor Kimura had found the needle in the plastic stack. He called it Ideonella sakaiensis.

For a while people were mildly interested, there was a flurry of pressproclaiming the solution to the plastic problem may have been found. But soon the excitement died down, for this was still two years before the dead whale cub was beamed into homes around the world. And so the newly discovered I. sakeienis slipped from the folk mind. That was until, a second breakthrough came. Perfectly timed, on this occasion, coinciding with the new anti-plastic movement. Professor Kimura had been happily sharing his cultures with scientist far and wide, and and one group had accidentally genetically engineering the protein that empower I. sakeienis to be a much more efficient plastic digester. In those 24 months they had done what nature might have taken centuries to achieve. The bacteria hit the headlines. They showed the world that by taking what Gaia started and combining it with 21st century biotechnology we could at last tackle the plastic problem of our own making.

Genetically modification of organism, vilified for decades as the technology that would destroy our ecosystems, suddenly became the answer to all our worries. Folks who had ripped up experimental GM crops, fell over each other in their efforts to support genetically enhanced plastic munching microbes. After all, the plastics were unnatural and evil. And so, they reasoned, it was perfectly acceptable (at least in this case) to utilise GM bugs to clear up our mess. It might even be that we were just giving nature a helping hand, it was possible that some organisms might even have made a start on the plastics in the oceans.

The great cleanup began. Governments and eco-charities around the world throw money at the problem. What started with the odd publication here and there became a torrent of papers describing newly discovered and genetically enhanced bacteria, fungi and even worms. All equipped with an arsenal of plastic eating enzymes. Soon concerned citizens got in on the act. School science fairs featured projects dreamt up by keen children attempting to breed plastic-eating creatures, the maker movement got involved, as they discovered home bio-hack kits could be used to tinker with microbes molecular machinery.

By 2022 we had identified thousands of organisms, both naturally evolved and artificially enhanced, equipped with the molecular and mechanical machinery required to set to work on our poly-materials. In just a few more years the impact was tangible. Recycling plants quickly harnessed the new biotech boom to turn rubbish into fuel and chemical feedstocks used to create, amongst other things, fresh virgin plastics. Plastics production and recycling had at last become a truly circular economy. It even became economically viable, with the help of solar powered drone barges, to sweep up the great ocean garbage patches.

The oceanic rubbish rafts shrank, plastics slowly rotted on our beaches, reports of plastiglomerate dwindled. There was a collective sigh of relief.

Except it wasn’t just the rubbish the new breed of bugs were eating. Once out in the wild they were unable to distinguish between refuse and infrastructure. Whether the plastic-munching organisms escaped from the recycling plants, the amatuer bio-hackers’ sheds, or just naturally evolved, we can’t be sure.

The world was once crisscrossed with polythene pipes delivering gas and water to homes and industry. PVC insulated electrical cables and sheathed the world’s fibre optic communication networks. The many uses of plastics were incalculable. At its peak 350 million metric tonnes of plastic materials produced annually had formed the fabric of not just our single use packages, that we so quickly discarded, but also the very structure of our civilisation. And now that fabric rots like so much soft-wood.

By May 8, 2018 10 comments opinion, science news