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Assis. prof. Anton Gradišek and colleagues published a paper Bumble bee nest thermoregulation: a field study in Journal of Apicultural Research. They studied six bumblebee colonies of different species using a home-made setup. The study focused on the nest thermoregulation, which is important in order for the larvae to develop properly. They identified some thermoregulation strategies that have not previously been reported in bumblebees.

Abdelrahim Ibrahim Hassanien, PhD from the Department of Condensed Matter Physics F5 and colleagues from Germany have published in Particle & Particle Systems Characterization the article Neuronal-like Irregular Spiking Dynamics in Highly Volatile Memristive Intermediate-scale AgPt-Nanoparticle Assemblies.

Neuromorphic computing seeks functional materials capable of emulating brain-like dynamics to solve complex computational problems. Interestingly, the transport properties of memristive materials show feature that is closely oriented toward the behavior of artificial neurons. However, artificial neurons are rather rigid mathematical concepts than realistic projections of complex neuronal dynamics.

Neuroscience suggests that highly efficient information representation on the level of individual neurons relies on dynamical features such as excitatory and inhibitory contributions, irregularity of firing patterns, and temporal correlations. Here, a conductive atomic force microscopy approach is applied to probe the memristive dynamics of nanoscale assemblies of AgPt-nanoparticles at the stability border of the conducting state, where physical forces causing the formation and decay of filamentary structures appear to be balanced. This unveils a dynamic regime, where the memristive response is governed by irregular firing patterns. The significance of such a dynamical regime is motivated by close similarities to excitation and inhibition-governed behavior in biological neuronal systems, which is crucial to tune biological neuronal systems into a state most suitable for information representation and computation.

Assistant Professor Anton Gradišek and Professor Tomaž Apih, together with colleagues from Lisbon, Portugal, published a study Observing short-range orientational order in small-molecule liquidsin the journal Scientific Reports. The authors address a phenomenon that has been known for decades in the scientific community, but never systematically addressed. In the isotropic phase of liquid crystals, far from the clearing point, we can still observe short-lived clusters with local ordering. The same phenomenon was observed also in liquids that do not even form a liquid crystalline phase. The analysis was conducted with the use of NMR relaxometry and X-ray diffraction. The findings are important in view of understanding the crystallization process.

Jampani Venkata Subba Rao, PhD from the Department of Condensed Matter Physics F5 and colleagues from Luxembourg have published in Small the article Continuous Flow Microfluidic Production of Arbitrarily Long Tubular Liquid Crystal Elastomer Peristaltic Pump Actuators.

Liquid crystal elastomers (LCE) are produced using glass-based microfluidics tools in tube geometry. The key innovation is generating arbitrary long-aligned LCE tubes through shear flow and showing the peristaltic actuation mechanism using local heating.  Such tubes are the potential to generate active synthetic vasculature in biological contexts.

Turbulent flows in active nematic liquid crystals lead to spontaneous topological defect creation. Researchers Maruša Mur, Žiga Kos, Miha Ravnik and Igor Muševič from the Department of Condensed Matter Physics at the Jožef Stefan Institute and Faculty of Mathematics and Physics at the University of Ljubljana have published a paper in Nature Communications, titled Continuous generation of topological defects in a passively driven nematic liquid crystal, where they study a similar behavior in a passively driven system. Here, the flow is driven by a concentration gradient of small organic molecules added into a thin film of a nematic liquid crystal. Counter-rotating vortex rolls are generated in the film. Above a velocity threshold the flow transitions from a laminar into a turbulent regime, where topological defects start forming continuously. In the paper authors support their experimental findings by numerical simulations. The work describes one of the few mechanisms of topological defect creation in soft matter.