EPJ B Highlight - Fractal patterns in growing bacterial colonies

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Published on 18 September 2019

A new agent-based computer modelling technique has been applied to the growth and sliding movement of colonies of bacteria

As many people will remember from school science classes, bacteria growing on solid surfaces form colonies that can be easily visible to the naked eye. Each of these is a complex biological system in its own right; colonies display collective behaviours that indicate a kind of 'social intelligence' and grow in fractal patterns that can resemble snowflakes. Despite this complexity, colony growth can be modelled using principles of basic physics. Lautaro Vassallo and his co-workers in Universidad Nacional de Mar del Plata, Argentina have modelled such growth using a novel method in which the behaviour of each of the bacteria is simulated separately. This work has now been published in the journal EPJ B.

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EPJ E Highlight - Shocking embryonic limbs into shape

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Published on 18 September 2019

Electrical stimulation of early chicken embryos has shed light on the process through which the limbs of all vertebrates are formed.

Every vertebrate, whatever its eventual form, starts embryonic life in the same way – as a hollow ball or disc of cells called a blastula. In theory, knowing the mechanism through which the blastula is formed into the shape of an animal could help correct defects and even, one day, regenerate body parts. But evolution and genetics are of little help in understanding this process. Now, however, Vincent Fleury and Ameya Vaishnavi Murukutla from Université Paris Diderot, Paris, France have used experiments with chicken embryos to propose a mechanism for vertebrate limb formation. These findings have been published in the journal EPJ E.

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EPJ B Highlight - Conductivity at the edges of graphene bilayers

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Published on 11 September 2019

The conductivity of dual layers of graphene greatly depends on the states of carbon atoms at their edges; a property which could have important implications for information transmissions on quantum scales.

Made from 2D sheets of carbon atoms arranged in honeycomb lattices, graphene displays a wide array of properties regarding the conduction of heat and electricity. When two layers of graphene are stacked on top of each other to form a ‘bilayer’, these properties can become even more interesting. At the edges of these bilayers, for example, atoms can sometimes exist in an exotic state of matter referred to as the ‘quantum spin Hall’ (QSH) state, depending on the nature of the interaction between their spins and their motions, referred to as their ‘spin-orbit coupling’ (SOC). While the QSH state is allowed for ‘intrinsic’ SOC, it is destroyed by ‘Rashba’ SOC. In an article recently published in EPJ B, Priyanka Sinha and Saurabh Basu from the Indian Institute of Technology Guwahati showed that these two types of SOC are responsible for variations in the ways in which graphene bilayers conduct electricity.

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