Rogue antibodies causing long covid

Despite WHO declaring the COVID-19 pandemic at an end over a year ago, cases of long COVID persist in both those previously and newly infected. Symptoms of long COVID include chronic pain and severe brain fog, and continue beyond initial infection for at least three months.

There remain several hypotheses for what causes this disease, such as lingering copies of the virus. However, this study suggests that it could instead be a result of patients’ own defence; the immune system. Part of the immune response involves cells releasing specific proteins, antibodies, which bind to the pathogens (in this case SARS-CoV-2 viruses) to prevent them causing damage. While previously thought there could be a correlation between antibodies generated which wrongly attack the hosts’ own immune system and long COVID, this new research seems to show a causal relationship.

“This study suggests that it could instead be a result of patients’ own defence; the immune system”

Antibodies were extracted from blood samples of patients suffering from long COVID, and patients who had fully recovered from a COVID-19 infection (the control group). When samples were injected into mice, mice with proteins from the long COVID patients exhibited a higher pain sensitivity than the control group. Mice with another group of injected samples walked 40% less distance in half an hour than the control. This suggests that the antibodies from long COVID patients could be what is causing the painful symptoms – they are perhaps part of an overenthusiastic immune response in which healthy tissue is also targeted.

This is important for several reasons: better understanding can help lead to better treatment for long COVID patients, and regulations such as prevention of blood donations by long COVID patients can be put in place.

New equation predicts how quickly animals flap their wings

In a breakthrough in our understanding of animal flight, researchers in Copenhagen have developed a new formula that accurately predicts the speed animals beat their wings at, regardless of species or size. The equation relates wingbeat frequency to body mass and wing area, and can apply to any animals flying style, with the physicists behind it saying it matches biological data on insects, bats and flapping robots as well as birds and whales.

Tina Hecksher, leader of the study, expressed surprise at how “how well the data follows the prediction and kept expanding the data set to include other flying animals to see how far this universality goes,” and commented that, “when we saw that even swimming/diving animals follow the same line, we thought that this may interest a broader audience”.

This development is part of a long history of research into universal patterns in animal flight. In 1990, British biologist Colin James Pennycuick related wingbeat frequency to a bird’s body mass and wing expression, creating an equation for to accurately calculate the speed of bird wing-beats.

However, this new model is unique in that, unlike previous studies, it is able to predict wingbeat across species. All previous studies like that of Pennycuick’s were purely empirical, and did not aim to investigate general principles of all animal flight. This is something Hecksher credits the the study’s interdisciplinary nature for, claiming that the “formula is theoretically derived based on physics principles” and how, “this approach is less common among biologists…it takes the combination of physics and a large amount of empirical data to arrive at this result”.

Extreme impacts found to make metals stronger when heated

Our conventional understanding of metals is that heating them makes them softer, allowing for them to be manipulated and change shape. However, in an unexpected discovery, research by metallurgist Christopher Schuh has found that metals can actually become harder when deformed quickly during heating.

“When microparticles were used, the result is a clear indication of a ‘hotter-is-stronger’ effect”

In this research, Schuh used laser beams to propel microparticles of sapphire towards sheets of different metals at incredibly high velocities. When observing these collisions, it was found that particles bounced off the metal faster, the higher temperature it was. This indicating that the sample’s harness was increasing with heat, not decreasing.

When testing copper in their experiments, the researchers found that when increasing the temperature by 157 °C, the strength of the copper sample was boosted by about 30%. At 177 °C, the sample’s hardness increased still further, to the point where it was almost as hard as steel. This result is inherently counterintuitive since copper is a soft metal at low strain rates, meaning it would normally be expected to become softer at higher temperatures.

Schuh attributed this confusing result to the way the metal deforms when struck with microparticles, in an effect known as drag strengthening. At higher temperatures the vibrations of the metal’s crystal lattice become faster, and in doing so limit the chance of deformations that would be seen at lower temperatures. These results had not been seen before due to the size of the particles used; previous impact experiments used far larger particles, meaning there was a large shock-wave disrupting results. When microparticles were used, the result is a clear indication of a “hotter-is-stronger” effect.

This discovery could be applied when developing materials for extreme conditions, such as shields to protect spacecraft from meteorites or equipment for high speed machining practices, such as sand blasting.