Doctoral student Jonatan Jungmalm recruited a little over 200 recreational runners from the list of entrants for the Göteborgsvarvet Half Marathon and monitored them over a period of one year. To take part in the study, they had to have been running for at least a year, have run an average of at least 15 km per week over the past year and have been injury free for at least six months. The participants were men and women in the age range 18-55.

Calculation shows injury for half of runners

Over the year of the study, the recreational runners filled in a training diary, entering information about how far they ran each day and whether they felt any pain. Those who suffered sudden injury or felt pain for a prolonged period were examined by a sports doctor.

“A third of the participants were injured over the course of the study. But if you also take account of the participants who dropped out of the study, it is reasonable to assume that almost half of all recreational runners injure themselves in a year,” states Jonatan Jungmalm.

Jonatan used a particular statistical method to calculate the proportion of injured runners, taking into account the rate of dropout that is common in studies based on voluntary participation.

Injuries to knee, calf and Achilles tendon

Of those hit by injury, half had problems with their knees, calves or Achilles tendons.

“Few of the injuries were long-lasting. But all the injuries prevented the runners from exercising as usual,” says Jonatan.

No difference was found in terms of gender, age, running experience or weight between those who injured themselves and those who did not.

“However, those who had previously been injured were more likely to be affected again.”

Multiple physical tests

All the participants were put through a series of physical tests before the study, ranging from strength tests and mobility tests to tests of running style.

“Those who had relatively weak outer thighs faced a higher risk of injury. Those with late pronation in their running gait were also at higher risk. However, having a weak torso or limited muscle flexibility was of no great significance.”

Link to sport science thesis “Running-related injuries among recreational runners. How many, who, and why?”: http://hdl.handle.net/2077/67446

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Materials provided by University of Gothenburg. Note: Content may be edited for style and length.

Using EMBL Hamburg’s world-class beamline P12 at DESY’s PETRA III synchrotron, a team of Slovenian researchers, in collaboration with EMBL’s Svergun group, directed powerful X-ray beams at artificial proteins called coiled-coil origami. The proteins were designed to fold into a particular shape based on short modules that interact in pairs. By determining their molecular structure at the EMBL beamline, the researchers confirmed that the proteins folded into the desired shape and then studied the self-assembly process step by step. These findings advance understanding of how synthetic origami-like protein folding could potentially convey therapeutics, making it possible to more precisely target medication, minimising side-effects and maximising effectiveness.

“Recently scientists realised that natural proteins represent only a tiny fraction of possible protein shapes and that we can use design principles distinct from natural proteins. We can tailor designed proteins to make new materials, deliver drugs and vaccines, and much more,” says Roman Jerala, a synthetic biologist at the National Institute of Chemistry in Ljubljana, Slovenia, who led the work to design and build a bipyramid (a diamond shape made of two conjoined triangular pyramids) from different types of artificial protein chains.

While scientists first attempted origami using DNA, proteins lend themselves more to potential applications. Proteins are the molecular machines of life, containing long chains of amino acids that fold into shapes specific to the functions they serve. That can mean bolstering immunity, talking to other cells, or carrying out other tasks to keep the body healthy. The proteins used in this study were folded into braided ropes called coiled coils, which readily bind to other parts of the same chain or to other molecules. This makes them a particularly good building material for creating custom-made nanostructures.

Roman’s team first succeeded in this quest with a simpler origami structure — a single pyramid with a triangular base. They checked one chain of protein built of amino acids in a specific order and saw how it self-assembles. Then it was time to transform it from one structure to another, as if an origami lotus could transform into a crane. They put together two different chains of amino acids carrying a signal for a scissor enzyme called a protease, informing it where to make a cut in the origami protein. By doing so, they managed to force the protein to perform its origami transformation into a different shape.

Shining a light on protein solutions

To do this kind of work, the researchers need high-tech tools. EMBL Hamburg’s beamline P12 is particularly suited for this purpose, and EMBL’s Svergun group is known for its expertise in a technique called small-angle X-ray scattering (SAXS). Since 2018, EMBL scientists have been collaborating with the group from Slovenia, supporting them in using SAXS to study the structure of origami proteins.

“In SAXS, we shine X-rays at a glass capillary that contains the protein solutions. As the X-rays scatter as they pass through the solution, we have a way to interpret the structures,” says group leader Dmitri Svergun. “Here, most data collection work is automated, and we also provide important software and analysis support in collaborations like this one.”

Using the EMBL beamline, together with electron microscopy, calorimetry, computational modelling, and other methods, the researchers assembled the data needed to identify the structures of the origami proteins and confirm that the shapes would fit into their overall origami design.

“It’s our job to obtain the best signal from the beamline and create the optimal conditions for getting data,” says Stefano Da Vela, a postdoc in the Svergun group. “We provide tools to help make sense of the SAXS experimental data and create 3D models from the data.”

The researchers observed that their synthetic proteins assemble ‘bottom up’, which means that small, detailed bits form first and then assemble together into a bigger structure. Understanding this will help researchers construct more complex protein origami structures with more precision. “SAXS analysis was crucial in identifying which design leads to the desired shapes, and the superb tools developed at EMBL allowed us to detect unique features of our designed cages,” says Fabio Lapenta, a postdoc at the National Institute of Chemistry and the lead author of their recent paper in Nature Communications that described this work. “Coiled coils are excellent tools that can be used in cells as well as in isolated proteins. We think we can expand the potential of coiled-coil protein origami to design many new protein folds and introduce interesting functionalities.”

Why is sugar not transparent? Because light that penetrates a piece of sugar is scattered, altered and deflected in a highly complicated way. However, as a research team from TU Wien (Vienna) and Utrecht University (Netherlands) has now been able to show, there is a class of very special light waves for which this does not apply: for any specific disordered medium — such as the sugar cube you may just have put in your coffee — tailor-made light beams can be constructed that are practically not changed by this medium, but only attenuated. The light beam penetrates the medium, and a light pattern arrives on the other side that has the same shape as if the medium were not there at all.

This idea of “scattering-invariant modes of light” can also be used to specifically examine the interior of objects. The results have now been published in the journal Nature Photonics.

Astronomically many possible wave forms

The waves on a turbulent water surface can take on an infinite number of different shapes — and in a similar way, light waves can also be made in countless different forms. “Each of these light wave patterns is changed and deflected in a very specific way when you send it through a disordered medium,” explains Prof. Stefan Rotter from the Institute of Theoretical Physics at TU Wien.

Together with his team, Stefan Rotter is developing mathematical methods to describe such light scattering effects. The expertise to produce and characterise such complex light fields was contributed by the team around Prof. Allard Mosk at Utrecht University. “As a light-scattering medium, we used a layer of zinc oxide — an opaque, white powder of completely randomly arranged nanoparticles,” explains Allard Mosk, the head of the experimental research group.

First, you have to characterise this layer precisely. You shine very specific light signals through the zinc oxide powder and measure how they arrive at the detector behind it. From this, you can then conclude how any other wave is changed by this medium — in particular, you can calculate specifically which wave pattern is changed by this zinc oxide layer exactly as if wave scattering was entirely absent in this layer.

“As we were able to show, there is a very special class of light waves — the so-called scattering-invariant light modes, which produce exactly the same wave pattern at the detector, regardless of whether the light wave was only sent through air or whether it had to penetrate the complicated zinc oxide layer,” says Stefan Rotter. “In the experiment, we see that the zinc oxide actually does not change the shape of these light waves at all — they just get a little weaker overall,” explains Allard Mosk.

A stellar constellation at the light detector

As special and rare as these scattering-invariant light modes may be, with the theoretically unlimited number of possible light waves, one can still find many of them. And if you combine several of these scattering-invariant light modes in the right way, you get a scattering-invariant waveform again.

“In this way, at least within certain limits, you are quite free to choose which image you want to send through the object without interference,” says Jeroen Bosch, who worked on the experiment as a Ph.D. student. “For the experiment we chose a constellation as an example: The Big Dipper. And indeed, it was possible to determine a scattering-invariant wave that sends an image of the Big Dipper to the detector, regardless of whether the light wave is scattered by the zinc oxide layer or not. To the detector, the light beam looks almost the same in both cases.”

A look inside the cell

This method of finding light patterns that penetrate an object largely undisturbed could also be used for imaging procedures. “In hospitals, X-rays are used to look inside the body — they have a shorter wavelength and can therefore penetrate our skin. But the way a light wave penetrates an object depends not only on the wavelength, but also on the waveform,” says Matthias Kühmayer, who works as a Ph.D. student on computer simulations of wave propagation. “If you want to focus light inside an object at certain points, then our method opens up completely new possibilities. We were able to show that using our approach the light distribution inside the zinc oxide layer can also be specifically controlled.” This could be interesting for biological experiments, for example, where you want to introduce light at very specific points in order to look deep inside cells.

What the joint publication of the scientists from the Netherlands and Austria shows already is how important international cooperation between theory and experiment is for achieving progress in this area of research.

New research about Jupiter proves that point — and adds to the intrigue.

Peter Delamere, a professor of space physics at the University of Alaska Fairbanks Geophysical Institute, is among an international team of 13 researchers who have made a key discovery related to the aurora of our solar system’s largest planet.

The team’s work was published April 9, 2021, in the journal Science Advances. The research paper, titled “How Jupiter’s unusual magnetospheric topology structures its aurora,” was written by Binzheng Zhang of the Department of Earth Sciences at the University of Hong Kong; Delamere is the primary co-author.

Research done with a newly developed global magnetohydrodynamic model of Jupiter’s magnetosphere provides evidence in support of a previously controversial and criticized idea that Delamere and researcher Fran Bagenal of the University of Colorado at Boulder put forward in a 2010 paper — that Jupiter’s polar cap is threaded in part with closed magnetic field lines rather than entirely with open magnetic field lines, as is the case with most other planets in our solar system.

“We as a community tend to polarize — either open or closed — and couldn’t imagine a solution where it was a little of both,” said Delamere, who has been studying Jupiter since 2000. “Yet in hindsight, that is exactly what the aurora was revealing to us.”

Open lines are those that emanate from a planet but trail off into space away from the sun instead of reconnecting with a corresponding location in the opposite hemisphere.

On Earth, for example, the aurora appears on closed field lines around an area referred to as the auroral oval. It’s the high latitude ring near — but not at — each end of Earth’s magnetic axis.

Within that ring on Earth, however, and as with some other planets in our solar system, is an empty spot referred to as the polar cap. It’s a place where magnetic field lines stream out unconnected — and where the aurorae rarely appear because of it. Think of it like an incomplete electrical circuit in your home: No complete circuit, no lights.

Jupiter, however, has a polar cap in which the aurora dazzles. That puzzled scientists.

The problem, Delamere said, is that researchers were so Earth-centric in their thinking about Jupiter because of what they had learned about Earth’s own magnetic fields.

The arrival at Jupiter of NASA’s Juno spacecraft in July 2016 provided images of the polar cap and aurora. But those images, along with some captured by the Hubble Space Telescope, couldn’t resolve the disagreement among scientists about open lines versus closed lines.

So Delamere and the rest of the research team used computer modeling for help. Their research revealed a largely closed polar region with a small crescent-shaped area of open flux, accounting for only about 9 percent of the polar cap region. The rest was active with aurora, signifying closed magnetic field lines.

Jupiter, it turns out, possesses a mix of open and closed lines in its polar caps.

“There was no model or no understanding to explain how you could have a crescent of open flux like this simulation is producing,” he said. “It just never even entered my mind. I don’t think anybody in the community could have imagined this solution. Yet this simulation has produced it.”

“To me, this is a major paradigm shift for the way that we understand magnetospheres.”

What else does this reveal? More work for researchers.

“It raises many questions about how the solar wind interacts with Jupiter’s magnetosphere and influences the dynamics,” Delamere said.

Jupiter’s aurorally active polar cap could, for example, be due to the rapidity of the planet’s rotation — once every 10 hours compared to Earth’s once every 24 hours — and the enormity of its magnetosphere. Both reduce the impact of the solar wind, meaning the polar cap magnetic field lines are less likely to be torn apart to become open lines.

And to what extent does Jupiter’s moon Io affect the magnetic lines within Jupiter’s polar cap? Io is electrodynamically linked to Jupiter, something unique in our solar system, and as such is constantly stripped of heavy ions by its parent planet.

As the paper notes, “The jury is still out on the magnetic structure of Jupiter’s magnetosphere and what exactly its aurora is telling us about its topology.”