Here’s a fun fact: approximately 1 in 10 people in the world live within 100 km of an active volcano. Aside from causing mass evacuations, destroying huge areas of land, and ruining your travel plans, volcanic eruptions can have devastating health effects. Some research estimates about 540 people are killed by volcanic activity each year. At the moment, there’s no accurate way to predict when a volcano will erupt, but that could change thanks to the work of some Queensland scientists. To understand how this research works, first let’s talk volcanoes 101. Imagine the world like a Ferrero Rocher: a hard crust on top of a viscous mantle with a solid core in the middle (ok, there’s also a liquid inner core but that doesn’t fit with my analogy). Credit: A. Kniesel, Wikimedia CC BY-SA 3.0 The crust is relatively thin, like the skin on an apple, and it is broken up into tectonic plates that sit on the mantle. Volcanoes tend to occur where these tectonic plates meet and either run into each other or move away from each other. Weaknesses in the crust allow molten magma from the mantle to be pushed up, forming a volcano. Within the volcano, magma collects in magma pools, until the build-up of pressure from molten rock and gas forces the magma upwards through weaknesses in the surrounding rock. Eruptions occur when the pressure is so great the magma is pushed to the surface and the volcano explodes, releasing lava, ash and gases. A sudden influx of new magma into existing magma pools can be a trigger for a volcanic eruption. However, since each volcano is different and has complicated pathways from magma pools to the surface, it can be hard to tell how long it will take from a magma influx to an eruption for each individual volcano.
By looking at the chemical composition of tiny crystals and matching this with geophysical and eruption data from the past 40 years, a team of researchers at the University of Queensland has built a model to predict the eruptions of Mt Etna (Sicily, Italy) with a success rate of up to 90%. The crystals grow as magma starts to move up towards the surface of the Earth. The composition of the crystals change depending on their surrounding environment, and grow like tree-rings. By mapping the trace elements within the crystals, the researchers found chromium-rich zones, which suggest crystal growth shortly before eruption, that were surrounded by a chromium-poor ring, indicating surface crystallisation after eruption. By working on the premise that chromium-rich zones indicate the influx of new magma the researchers were able to suggest pathways for the flow of magma through Mt Etna, based on regular eruption events over the past decades. Based on these pathways and seismic data it is possible to predict that Mt Etna will erupt within 2 weeks of a magma influx. The researchers hope to apply this technique to other active volcanoes to better predict when eruptions will occur, allowing early evacuation, saving lives, and not ruining your next trip to Bali.
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Cracks in concrete are unsightly and expensive. They start off small but they can grow pretty quickly, and if water gets in the steel reinforcing underneath can be damaged and lead to structural failure. You can replace the concrete, but then it’s only a matter of time before cracks form again. So wouldn’t it be great if the concrete could just…heal itself? This idea is not actually as far-fetched as it might seem. Self-healing concrete is not new, and previous research has tried to accomplish this via three main processes. The first is autogenous healing. When water flows into a crack, cement particles in the crack are hydrated and calcification occurs due to dissolved carbon dioxide in the water. However, this only works for very small cracks and requires water. The second is the incorporation of a polymer matrix into the cement. When the polymer is exposed to humidity it releases a foam-like substance to fill the crack. Unfortunately, since this material behaves very differently to the concrete it can sometimes only make the cracks worse. The third method is bio-based: using calcium carbonate-producing bacteria to patch up the concrete. Bacteria are pretty good at this, but there are a few drawbacks, like increased nitrogen being released into the environment and needing a highly concentrated calcium source.
But now there’s a new kid on the block: fungi. A team of researchers at Binghamton University, State University of New York conducted an experiment analysing the interactions of various species of fungi with concrete. They found a fungus called Trichoderma reesei that is able to produce calcium carbonate, and can survive the drastic pH change that occurs as concrete dissolves. The idea is that this fungus will be mixed into the concrete. It will remain in a dormant spore state until a crack appears, exposing the spores to water and oxygen. When enough water and oxygen seep in, the fungus will wake up and begin growing and multiplying. As it does this it will precipitate calcium carbonate to fill up the crack. Once the crack is filled and no more water and oxygen can enter, the fungus will return to a spore state. The research is still in its early stages and the main challenge now is to make sure the fungus can survive within the concrete and throughout the concrete-making process, but bio-based concrete-healing is definitely a new technology to look out for. Self-healing concrete – coming soon to a neighbourhood near you? Imagine a world where a minor injury or infection could be a death sentence. It sounds like the dark ages, the pre-antibiotic era before WWII, but it could once again become reality. The world is fast running out of effective antibiotics. Bacteria have evolved resistance to all known antibiotics, and the prevalence of antibiotic-resistant infections is on the rise. The problem is so bad that the World Health Organisation predicts that in 2050 10 million people will die from antibiotic-resistant infections. Source. Image Credit: Katie McKissick Used with permission. Part of the problem is that it’s really hard to find new antibiotics. Many are based on natural compounds that other bacteria produce as a defence mechanisms, and here all the low-hanging fruit has been picked. Purely synthetic (man-made) compounds are another avenue, but often compounds that seem initially promising are later found to be ineffective because they can’t pass through cell membranes to actually kill the infection. Oh, and there’s never enough funding. Like with all drugs, antibiotic discovery has a high failure rate. The best way to get around this is to try lots and lots of compounds. I’m talking hundreds of thousands. No, not hundreds and thousands
To overcome these limitations, a team of researchers at The University of Texas at Austin has come up with a new technique to screen potential antibiotics: Surfaced Localised Antimicrobial Display aka SLAY (because everything in science needs a cool acronym, even if slightly contrived). Here’s my three favourite things about the technique:
Of the 800,000 random sequences, the team found 7,968 potential new antimicrobial peptides. They tested 22 of these against four different strains of bacteria and approximately 80% were active against the bugs. They’re now working on developing these active compounds further to make them even more effective. With any new compound it is only a matter of time before the bacteria evolve and catch up. Antibiotic resistance is inevitable. Like in the And the scientists working on it? I bet they SLAY all day. I know not everyone is a huge fan of spiders, but I think this guy is pretty cute: Photo credit Jean and Fred, Flickr. [CC-BY 2.0] He’s a Peacock Spider (Maratus spp.) and his way of impressing the ladies is to do a little dance, showing off his brightly coloured backside: As he moves, notice how the colours change all the way from purple to blue through to yellow and red. In fact, this little spider can show off all colours of the rainbow, depending on which way you look at him. Iridescence in nature is not uncommon – think of butterflies, peacocks and pigeons – but usually it’s over a very limited range of colours, like a blue that shifts from bluey-green to purple. It turns out this little spider is incredibly unique because he’s able to display every colour in the visible spectrum. So, how do these spiders make their rainbows? In a recent paper published in the journal Nature, researchers set out to answer just that. They used a range of imaging and probing techniques including electron microscopy and optical modelling to figure out how the spider scales display such beautiful colours. To understand iridescence we need to think about light as waves that can interact and interfere with one another. If two waves meet so their peaks line up, the peaks will add together and amplify the wave, making it twice as big. This is called constructive interference. On the other hand, if a peak meets a trough it will cancel out to nothing, which is called destructive interference. Iridescence can be caused by reflecting light multiple times over several semi-transparent layers, or by using a diffraction grating which splits incoming light into several beams travelling in different directions. In both of these cases it is constructive interference that creates iridescence. The researchers found the spiders have a microscopic 3D surface that is curved a bit like an aerofoil. Over this surface they have a nanoscale diffraction grating. The interaction between the grating and the curved surface means that light hitting the scale is separated out into its individual colours resulting in a beautiful rainbow.
The researchers then used nanoscale 3D printing to try and mimic the spider’s intricate structures in order to confirm their hypothesis. Our current technologies are not capable of resolving and separating white light into individual colours at short distances, but inspiration from these spiders’ scales could help improve optical technologies. In particular it could reduce the size of spectrometers used in space missions, or even lead to wearable chemical detectors. Who knows, at some point in the future we could all be using spider-inspired technology! |
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Emi Schutz Archives
March 2018
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