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AI: Thinking in Three Dimensions
A Stomach-Churning Discovery
A classical problem in structural biology is the ‘protein folding problem’ — that is, figuring out what final 3D conformation a protein takes. The 3D shape of a protein is important as it is closely linked to its function, but there are many theoretical ways that one protein could fold into its final shape. Biologists have traditionally resorted to expensive and laborious techniques for solving the problem, such as nuclear magnetic resonance and x-ray crystallography. However, DeepMind’s revolutionary artificial intelligence (AI), AlphaFold, could provide a much more accessible solution. British AI company DeepMind, co-founded by Cambridge alumnus Demis Hassabis, specialises in designing neural network systems: each is a series of computer algorithms that collectively act like a human brain, in that they can extract and learn underlying relationships in a dataset and apply this to new data, albeit much more powerfully. Learning from past examples, AlphaFold is able to take the sequence of amino acids that make a protein — its building blocks — and predict the final 3D structure with incredible accuracy: better than all other teams that entered the CASP14 protein folding contest and very close to the experimentally determined structures. Although experimental data still remains the gold standard for determining protein structure, AlphaFold’s immediate impact will be to reduce the amount of data needed to reliably predict a protein’s 3D shape, empowering research that was simply not feasible beforehand. AL
Our impulse to look away from disgusting images is triggered by changes in the electrical rhythm of our stomach, according to new research from the MRC Cognition and Brain Sciences Unit at the University of Cambridge. The study, published in Current Biology, showed that domperidone, an anti-nausea medicine which acts on this stomach rhythm, was able to significantly reduce the time volunteers spent looking away from a series of disgusting images. The effect of domperidone is to stabilise the rhythm of electrical signals in the stomach muscles — signals which can cause involuntary vomiting if strongly disrupted by powerful feelings of revulsion. In the study, some volunteers were given domperidone while others received a placebo, and they were then shown a selection of disgusting and neutral images. At a certain point in the study, the volunteers were given a monetary incentive for spending longer looking at the disgusting images. The researchers found that, in the round of testing after the incentive was applied, volunteers who had been given domperidone spent significantly longer than the placebo group looking at the disgusting images. ‘We’ve shown that by calming the rhythms of our stomach muscles using anti-nausea drugs, we can help reduce our instinct to look away from a disgusting image’, explained Professor Tim Dalgleish, one of the researchers from the MRC Unit, ‘but just using the drug itself isn’t enough: overcoming disgust avoidance requires us to be motivated or incentivised. This could provide us with clues on how we can help people overcome pathological disgust clinically, which occurs in a number of mental health conditions and can be disabling.’ ZLB
Making a Map of the Universe
The Gaia mission was launched in 2013 and aims to help us map the universe, as there is still a great deal of uncertainty in the distances of the stars and galaxies around us. Knowing the distances to nearby stars may help calculate brightness of the stars and model stellar evolution. From this rudimentary interstellar ruler, it is possible to measure the distances and brightness of nearby galaxies, and even those distant enough that individual stars cannot be observed. Recently, the European Space Agency has released a new round of preliminary data from the Gaia mission, featuring an additional 34 months’ worth of observational data including new types of analysis on a much bigger scale than before. The most accurate way of measuring interstellar distances — short of travelling to the stars themselves — is to measure the infinitesimal shifts, or parallax, of these pinpoints of light over the course of half a year as the Earth moves from one side of its solar orbit to the other. Gaia is well suited to measure these parallaxes with greater precision than ground-based telescopes, which must contend with the distortion of incoming starlight by ripples in the atmosphere. The new information will ultimately help in determining the distribution of mass in the universe, and the high precision to which objects can now be localised in the sky will also be useful in other areas of physics, such as the detection of exoplanets or multiple-star systems. This astounding new data is only part of the full dataset which is scheduled for release in the middle of next year. CS
Artwork by Josh Langfield
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Lent 2021
